Downloads suddenly stopped working, getting error message

We have had downloadable Ebooks and audio and video in MP3 and .zip files for many years with very few problems.

Recently any attempt to download one of the items results in a pop-up with an error message that reads;
"C:\DOCUME1\pcuser\LOCALS1\Temp\JdxqPLpT.jpg.part could not be saved, because the source file could not be read.

Try again later, or contact the server administrator."

All the downloadable files appear to be valid and unchanged, all attribute settings are unchanged.

I have opened a support ticket with the hosting company but they are just throwing it back to me saying the problem is in zencart. However, I have two separate zencarts on this server account and they both have the same error happening.

'Any ideas?

C:\DOCUME~1\pcuser\LOCALS~1\Temp\JdxqPLpT.jpg.part could not be saved

The tilde's in the path are of concern - is that a valid path??

1.3.8a - If you are using this old version that has known vulnerabilities, known since Jul 2006
You need to upgrade before you are discovered and hacked

kobra:

C:\DOCUME1\pcuser\LOCALS1\Temp\JdxqPLpT.jpg.part could not be saved

> The tilde's in the path are of concern - is that a valid path??
> 
> 1.3.8a - If you are using this old version that has known vulnerabilities, known since Jul 2006
> You need to upgrade before you are discovered and hacked

Yeah I'm working on getting it upgraded and will prob move to a new webhost as well soon but I'd really like to solve this downloads issue ASAP.

Update: This problem seems to be solved by turning GZip compression off.

Thanks for the update -

How did gzip get set initially??