During an IND$File transfer file send File Open, there was an error detecting the file's size...
Try checking the Windows Security settings for the c:\programdata\inventu\DataXfer (substitute flynet for inventu if older installation)--
If the security for the DataXFer folder looks off and is missing any of the following, update and include:
You can also perform a Selective trace with a user's cooperation to reproduce the error, open a ticket and provide the trace files to Inventu Support.