Workflows not completing

[Scott, Jason J.]

I have a workflow which includes 1 background task. The workflow is
triggered by an event and starts successfully. The background task
executes successfully and gets the status "completed" - however the
overall workflow stays in status "in process".
 
No errors are seen anywhere?
 
We cannot manually complete the workflow either - we get the message
that "'Complete Manually' is not available for this workitem".
 
Has anyone seen this type of problems before..? We do not use any form
of deadline monitoring on this workflow so it is a real mystery. We have
plenty of other workflows that all successfully complete.
 
A point of note is that the background task does some file operations
and an ftp - it still completes successfully though.
 
Thankyou for your help,
 
 
Jason Scott.