It looks like your tar archive was written with absolute paths. AFAIK you are going to be stuck with those paths if you are using the
tar executable. I have had a quick look at the
Archive::Tar module and there are some methods shown in the documentation that might help you out. However, I haven't used that module so I might be wrong. If it is possible, it might be quicker to re-create the tar archive with relative paths.
I hope this is of use.
Cheers,
JohnGG
Update: I didn't explain that last very well. What I mean is change $UploadDir in your script so that it contains a relative path rather than an absolute one and do a chdir to where that relative path starts before running the tar command.