I am having a problem installing iPrint printers. It is happening more
often than not, and is also affecting the automatic install of printers
via a Zen Policy.

Workstations are Windows XP with all latest patches. Servers are
Netware 6.5 SP5. iPrint Client is 4.28.

When I try to install a printer it fails with the error message
"Overlapped I/O operation is in progress. Error Group: Windows, Error
Code: 997"

It is intermittent, though happening maybe 60% - 70% of the time. On one
machine, I can sometimes get the install to work, more often not.
Likewise running the ZFD iPrint policy manually will sometimes work,
sometimes not. It is happening on different types of machines (though
all with essentially the same programs and patch levels.

Any suggestions would be most welcome, as lynching by users is looming!