IOException in WAS 3.02 or WCS 4.01 ?

Hi everyone,
we' are using Websphere Application Server (WAS) 3.02 and Websphere
Commerce Suite (WCS) 4.01 (on AIX platform) for our application. Now
and then we get an IOexception with following message "Error during
native write operation! Status Code: -1". We don't use any direct
write operation in our application, so we are thinking WAS 3.02 or WCS
4.01 is the reason for the IOException.

Thanks in advance for any help!

Borny