BUG #2099: too many private dirs ?

The following bug has been logged online:

Bug reference:      2099
Logged by:          Tom
Email address:      tom.zschockelt@flender.com
PostgreSQL version: 8.1.0
Operating system:   win2003 server
Description:        too many private dirs ?
Details:

we got the following error in our environment:

2005-12-08 13:43:04 ERROR:  too many private dirs demanded
2005-12-08 13:43:04 ERROR:  checkpoint request failed
2005-12-08 13:43:04 HINT:  Consult the server log for details.

Our environment is the following :
1 x win2003 server with postgresql 8.1.0-2
DB-Data on a NAS-device (mounted as network drive)

The error occurs when we want to create a new database in the
postgres-cluster. Creation of databases are only possible a few hours after
restarting the postgres
service.

Any idea ?