System i Navigator .DLL goes missing when trying to remote in?

Our shop uses Windows' (7 Ultimate SP1) Remote Desktop Connection whenever
we need to log into our own desk PCs from another PC, like say from a
learning lab.

Yesterday, we had a class in the learning lab that involved using System i
Navigator (the Windows client) and, after I remoted (?) in to my desk PC, I
started up Navigator, but was met with some CWB******.DLL was missing.
When I returned to my desk, I tried again, and got the same error.  I
rebooted, and I was back in business.

Anybody seen this before?  And know how to fix?

- Dan