EM app-profile install location doesn't support pointers to extensions on different drives. This bug is caused by the bug in the GetRelativeDescriptor implementation. I think that we should probably only use a relative file descriptor for app-profile when the extension is in a subdirectory of the extensions/ folder. Otherwise, we should use an absolute descriptor. Another approach would be to fix nsLocalFile. This isn't a critical bug since this use case is pretty infrequent and would only be hit by extension developers, but it does seem like something worth fixing if we have time before Firefox 1.5.
Are you sure about this? I could have sworn that I fixed this with the check at http://lxr.mozilla.org/mozilla/source/toolkit/mozapps/extensions/src/nsExtensionManager.js.in#383 (only use relative descriptor if the profile dir "contains" the extension dir).
Ah, I think DPA2 was being tested at the time. |itemLocation| is definitely the location of the directory, and not the location of the pointer file, right? I will test to confirm that this is fixed on the trunk...
*** This bug has been marked as a duplicate of 291807 ***