Problem:
When you are running QLI, and if you have submitted
a query, for which InterBase needs to create sort files, it
usually does it in the /tmp directory, unless defined otherwise.

If you get the above error message, it means that InterBase
was not able to write/create sort files for your query
processing..

One cause of this to happen was if /tmp was not set with the
permissions  of "666".   


Solution:
 Check to see if the /tmp directory is set to 666.