The MSComm Error 8021 with desc.: "Application-defined or object-defined error"
Rino Ouellet
Can someone tell me the possible causes of the error I have?
I have the error 8021 (Application-defined or object-defined error) in a Sub
that contains the line
FrmMain.MSComm1.Output = (Q$)
where Q$ is a string we send on Com1. It contains some other lines, but it
only assign a variable to the value 5 and set an Image visible and another
image invisible.
In the current circumstance, I suppose the error 8021 is caused by MSComm
control. The description of the error 8021 for MSComm control is "Internal
error retrieving device control block for the port".
So what could be the causes of this "Internal error retrieving device
control block for the port"?
Note: The error happens on our client's computer but we can't reproduce the
trouble on our computer and it seems to work properly here. I use Visual
Basic 6.0.
Thank you!
--
My E-mail: rinouell...@globetrotter.net
Randy Birch
error, here's another wild-ass guess that may explain why your user
experinces a failure but you don't.
Multihomed Master Browser May Cause Event ID 8021 and 8032
Q135404
--------------------------------------------------------------------------------
The information in this article applies to:
a.. Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
b.. Microsoft Windows NT Server versions 3.5, 3.51, 4.0
c.. Microsoft Windows 2000 Advanced Server
d.. Microsoft Windows 2000 Server
e.. Microsoft Windows 2000 Professional
--------------------------------------------------------------------------------
SYMPTOMS
Your computer running Microsoft Windows NT or Windows 2000 may occasionally
log one or more of the following events in the Event Viewer System log:
Event id: 8021
Source: Browser
Description: The browser was unable to retrieve a list of servers from the
browser master <PDC> on the network \device\<protocol_netcard>. The data is
the error code.
-or-
Event id: 8032
Source: Browser
Description: The browser service has failed to retrieve the backup list
too many times on transport of <protocol_netcard>. The backup browser is
stopping.
This symptom occurs if:
a.. Your computer is a multihomed computer (that is, it may link
simultaneously to two or more subnets using multiple network cards).
b.. Your computer is a master browser.
c.. Your computer is running the TCP/IP protocol.
CAUSE
The following situations can cause this symptom:
a.. Your computer network cards are linked to the same subnet.
b.. Your computer network cards are not linked directly to the same
subnet, but are linked indirectly through other subnets that they are
connected to.
c.. The master browser is using an incorrect subnet mask.
WORKAROUND
To work around this problem, do one of the following:
a.. Unbind all but one of the TCP/IP subnet transport bindings from the
workstation service.
-or-
b.. Remove all but one of the network cards or RAS connections.
-or-
c.. At the command prompt type the following command:
net stop browser
NOTE: This option prevents you from receiving computer browse lists from
other networks.
After you perform these steps, wait at least 10 minutes to see if the errors
still occur. If they do, continue troubleshooting by cross- referencing 2
pieces of information. First, check the transport that failed in the event
log. For example, error 8021 displays a message similar to the following:
The browser was unable to retrieve a list of servers from the browser
master \\<server_name> on the network \Device\NetBT_<driver_name>. The data
is the error code.
The important data is NetBT_<driver_name>, which indicates the protocol and
netcard binding, also known as an "endpoint." The potential protocols you
may see are:
Nbf_netcard = NetBEUI NetBT_netcard = TCP/IP (or NetBIOS over TCP/IP)
NwlnkIpx = IPX/SPX (NwLink) [will not indicate netcard] NwlnkNB = NetBIOS
over NwLink [will not indicate netcard]
After you have determined the failed protocol endpoint, check the working
status of the Browser service on all installed protocols with the Windows NT
resource kit program Browstat.exe. At a command prompt, type the following
command:
browstat status
This will enumerate the browser status on all endpoints. Look for the
message Browser is NOT active on domain under each endpoint. Disregard data
about endpoints that list "NdisWanX" (such as Device\NetBT_NdisWan5); these
are RAS endpoints and will usually list the error anyway.
You should find a protocol match between these two steps. The next step is
to record any important information about the protocol from Protocol Setup
in the Network tool in Control Panel. Then, remove the protocol, restart the
computer, and see if the error no longer gets logged (remember to wait at
least 10 minutes). Then, try reinstalling the protocol, checking for the
error, and reapplying the service pack that exists on the current Windows NT
installation.
If the error persists after a protocol reinstallation, you may have problems
with the network adapter card. Check with the vendor to see if there is an
updated driver, or try another network adapter card.
STATUS
Microsoft has confirmed this to be a problem in the Microsoft products that
are listed at the beginning of this article. We are researching this problem
and will post new information here in the Microsoft Knowledge Base as it
becomes available.
Additional query words: tcpip multi-homed multi homed
Keywords : kbnetwork
Issue type : kbbug
Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search
kbWinNT351xsearch kbWinNT350xsearch kbWinNT400xsearch kbWinNTW350
kbWinNTW350xsearch kbWinNTW351xsearch kbWinNTW351 kbwin2000AdvServ
kbwin2000AdvServSearch kbwin2000Serv kbWinNTSsearch kbWinNTS400xsearch
kbWinNTS400 kbWinNTS351 kbWinNTS350 kbwin2000ServSearch kbwin2000Search
kbwin2000ProSearch kbwin2000Pro kbWinNTS351xsearch kbWinNTS350xsearch
kbWinAdvServSearch
Last Reviewed: February 12, 2001
© 2001 Microsoft Corporation. All rights reserved. Terms of Use.
--------------------------------------------------------------------------------
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--
Randy Birch
MVP Visual Basic
http://vbnet.mvps.org/
Please respond only to the newsgroups so all can benefit.
"Rino Ouellet" <rinouell...@globetrotter.net> wrote in message
news:wNNWc.51986$X12.24140@edtnps84...
: Hello.
:
:
Rino Ouellet
But I forgot to tell you the following details:
-The word client, here, means a person which is a client of our company.
-I use : Windows 2000 Professionnal Service Pack 4 (to develop the
application using Visual Basic 6.0 Professional Edition)
-Our client use : Windows XP (to run the .exe I made with Visual Basic)
-Note: I think the MSComm control causes the error.
So I would like to know possible causes of this error. I would (also) like
to know what could cause an error retrieveing the Device Control Block when
using MSComm control, even if you think it's not related to the current
problem (because this error happens sometimes on the computers of our
clients).
Thank you
--
Rino Ouellet
Multi-Électronique
Courriel/E-mail: rinouell...@globetrotter.net
"Randy Birch" <rgb_rem...@mvps.org> wrote in message
news:eQmDARii...@TK2MSFTNGP10.phx.gbl...