Using ActiveX in a forked thread...

I am writing a program that monitors some data in the background but needs
an interactive UI (very simple for now, just displays a list, and cancels
the operation).  My first instinct was just to use fork, like:

[obj startLoopThatCallsActiveXStuff] fork.

This caused a bunch of GPF's in the middle of getting my data via an ActiveX
interface and killed the Dolphin image.  I tried this a few times, I even
tried to step through it.  It still caused the GPF's.  Next I tried it like
this:

[obj startLoopThatCallsActiveXStuff] forkAt: Processor
userBackgroundPriority.

This worked without any apparent problems.  Will this be reliable, or am I
just solving the symptoms rather than the problem?  Are there any known
issues to watch out for when using ActiveX stuff in a forked thread?

Any thoughts?

Chris