Corrupt files after uploading

After uploading a file using Collabtive, the file shows up in the system but can not open it. Receives a message that the file is corrupted.
I have Collabtive version 2.0 and after the upgrade problems began.
What can cause these problems?
Regards
Chris
I have Collabtive version 2.0 and after the upgrade problems began.
What can cause these problems?
Regards
Chris