[Projects 2.0] :File Space Issue

[Projects 2.0] :File Space Issue

I am under my 10MB limit and only have 8 docs attached to my project, but I cannot upload any new documents for the project or create one. I comtinuously get this message:

"Why file(s) is/are not getting uploaded ?

Allocated disk space full
Diskspace for the portal is full. Kindly contact your administrator to upgrade to next suitable plan for additional diskspace or you need to clear unused datas & files."

How do I clear the "unused space" to accommodate the uploading of additional docs?

Scott