Difficulty in Receiving Email - 501 5.5.4 Invalid Arguments

[Shanel]

I look after an Exchange Server which receives email from a Scalix Mail
Server located at the Business Head Office. The mail server forwards email
out to clients on a different domain name at each location where an Exchange
Server is located.
One particular Exchange Server is logging the following MSExchangeTransport
SMTP Error in the Application log (Event ID:7010) whenever email is received
from users who send messages via a Blackerry device:

This is an SMTP protocol log for virtual server ID 1, connection #32. The
client at "xxx.yyy.zzz.189" sent a "mail" command, and the SMTP server
responded with "501 5.5.4 Invalid arguments ". The full command sent was
"mail From:<SRS0=/iK8Sy=TA=lasseters-intl.com=pa...@srs.bis.ap.blackberry.com>
SIZE=63864
ENVID=6336715-1202745597-cardhu_decombobu...@bxe002.bisx.prodap.on.blackberry
RET=FULL". This will probably cause the connection to fail.

The Exchange Server is Exchange 2003 SP2 running on 32Bit Windows 2003 R2.
The confusing thing is other Exchange Servers within the organisation can
receive email from Blackberry clients.

This is the only email that the server has difficulty receiving.

I think the syntax of the 'mail' command is wrong but cannot explain why the
other Servers receive it OK. Can anybody help me with this issue please?