Could not read - Permission denied

Hello,

 

We´re running 8.0.4 in a Windows XP box and some of the applications are not working...

 

Searching pg_log we´ve found the following messages:

2005-12-17 07:26:54 ERROR:  could not read block 3 of relation 1663/17253/104561: Permission denied
2005-12-17 09:26:11 ERROR:  could not read block 3 of relation 1663/17253/104561: Permission denied

What can be causing this error?

 

Thanks!

 

Engelmann