-Are you using the import functionality to upload the files?
-What is the size of these files?
-Are you importing all files at once?
-Check the log files for additional errors.
It could very well be the JRE/JVM version - what version are you using in your browser? What browser are you using? For that matter, what version of TeamSite are you using?
This issue was resolved by update JRE to version 6 at client side.
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