Make sure your checking the product in the repository and not via the extensions page.
Refer to the ReadMe below if you have not already for the Product.
Specifically look at Integrating using ePolicy Orchestrator 4.5/4/6 and the note.
If that fails restart all the ePO services and try again. That worked for me once.
It sounds more like a disk-space issue personally. You'd not get a message like that by trying to check a package in as an extension or vice-versa.
How much space is there on the drive hosting the \DB\Software folder of the ePO server ?
Failing that how big does the McAfeeVSEForLinux-1.7.0-28611-EPO.ZIP think it is.
I have more then enough space. the zip file is 379 MB.
But I think I found the problem the file I am trying to checkin does not have the EPO in the string. but I cannot find a file with the EPO in the string. hmmm....
My file name is mcafeeVSEForLinux-1.7.0-28611.zip. no EPO
I have the same issue on two ePO servers, both with more than enough disk space etc. Did you ever figure out how to check in the Linux 1.7 package? I'm on 4.6p1, but the error is identical to what you saw.