shortURL problem

I'm running a xaraya install on a hosted server. If I turn on the
shortURL support visiting a page through its shortURL does not work. It
either gives back a blank white page (4 times out of 5) or it gives me
an error message like this:

Warning: Unknown(): open_basedir restriction in effect.
File(/USER/fairvilag/fairvilag_org/www/index.php) is not within the
allowed path(s):
(/USER/nuskull:/USER2/nuskull:/servers/php/lib/php:/tmp/phpsession:/tmp/phpupload:/tmp/pear) 

in Unknown on line 0

Warning: Unknown(/USER/fairvilag/fairvilag_org/www/index.php): failed to
open stream: Operation not permitted in Unknown on line 0

Warning: (null)(): Failed opening
'/USER/fairvilag/fairvilag_org/www/index.php' for inclusion
(include_path='.:/servers/php/lib/php') in Unknown on line 0

where 'nuskull' changes with every request to something else.

I tried contacting my service provider, they have no idea what goes
wrong. Any suggestions of what might be the problem/ how to fix this?


Thanks,
Tamas