Christina,
I haven't really worked much with PHINMS since retiring, but here is what I recall... There are a couple of sender "processes" running that handle outgoing messages.
The sender "transport" process looks through the outgoing queue for files waiting to send. The location for those files are configured for the queue's database and is typically shared\outgoing by default. It is however restricted to a subfolder within the sender's "installDir" (prefix tag in sender.xml).
The other process (in your case) is the "folder poller". It runs through the list of outgoing folders you have set up (foldermap.xml) and when it finds a file it copies it to the database's shared\outgoing folder (or
whatever is configured for your sender's transport database - see above). Once done, it adds an entry for that file to the out going transport queue. It also moves it to the processed folder you set up (also configured in foldermap.xml). If for some reason
(say file permissions) it can't make the processed move, it just silently fails (sigh). Either way, the file must "disappear" from the folder map's outgoing folder so that is doesn't get queued more than once.
So for your immediate problem I would check that the PHINMS process has the needed file and folder permissions. If would not be out of my experience to have an over zealous security person change permissions somewhere (folder, group, or PHINMS user account) without asking.
Hope that helps
Tom