Cannot use path variable in output folder

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a path variable (e.g. VAR) that points to a valid place.
2. Create a mapping for a project using the path variable as the first segment 
of the target path, e.g. VAR/subdir1/subdir2
3. Press ok to validate entry

What is the expected output? What do you see instead?
Sync should happen since mapping has changed.
Instead, it fails with the following errors:
No valid FileMapping for project 'P/Test FileSync'
Could not create directory 'VAR/subdir1/subdir2'

When returning to FileSync propertied page for the project, target path has 
been changed to /VAR/subdir1/subdir2 (leading / added).

What version of the product are you using? On what operating system?
Eclipse 3.6
FileSync 1.3.6.201005301956
Arch Linux 64 bit

Please provide any additional information below.
Usage page on the web indicates:
> One could also use path variables for %destination folder%  or first part
> of it. This path variables are listed under "Window ->Preferences
> ->General ->Workspace->Linked resources-> Defined path variables". Usage
> is restricted to the first path segment only, see Javadoc for
> IPathVariableManager.resolvePath() on Eclipse site.

The latter mentioned method is now obsolete. Somehow, just like for issue #19, 
the code needs to be modified to use new api that takes into account variables 
path (has it ever worked?)

Furthermore, the target folder widget would also benefit from a refresh, using 
as example org.eclipse.ui.internal.ide.dialogs.PathVariableDialog. (Variable... 
and Browse... buttons)

Original issue reported on code.google.com by fmjrey on 25 Aug 2010 at 4:31