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