Sorry for the very late response :-( .
Seems, I didn't get an email about this report and didn't look into that corner of the web page at that time ...

Your right. Thanks for the report! (Hope you still use storeBackup ;-) )

I added ERROR messages because the program cannot do anything useful when getting the conditions you described. I didn't change it in subroutine absolute path because there theres no information about the meaning of the (relative) path. It's more work to add the ERROR messages in the programs directly, but it's easier to make them individually.

This patch will be included in the next release.

BTW, simply using absolute paths bypasses the issue.

After some problems with storeBackup*.pl, like storeBackupRecover.pl failing with "could not find info file ...", I was finally able to track the error down to the subroutine absolutePath in fileDir.pl:
On my ubuntu installation, I use "sudo storeBackup...". In this call's environment, there is no $PWD set (don't know why, but obviously never needed it before). Verified via sudo perl -e 'print $ENV{PWD}' => prints nothing.
In sub absolutePath, there's a line
$dir = $ENV{'PWD'} . "/$dir" unless ... With $PWD not set, this yields incorrect results ("some/path" => /some/path").

This can be fixed by the use of the standard module Cwd (which even contains a function abs_path...).

Thank you!