Move command return with exit code of 2

I have a script which loads data files into Oracle and then moves each file into a 'processed' directory when each file has finished loading.
Last night I found that the script was failing on the mv statement (with a return code 2) and the following message,

mv: cannot access /opt/ISSC/eai/interfaces/rss/import/RSS.RFP.OF01.dat

However when I had a look in the 'processed' folder the file RSS.RFO.OF01.dat was present there and it was not in the source folder any more. So from what I can see the move seems to have worked fine.

Can anyone shed any light as to why this might have failed or what a return value of 2 means.

The most likely explanation is that you tried to move the file twice.