VB6 and .tlb crashing

I found an indexing program called "Wilbur" that I would like to use
at work.  It has OLE automation routines (via a type library) and I
have built a pretty simple search app in VB6.  Unfortunately... I keep
getting Exception Errors and OLE Automation errors.  The Wilbur
application runs fine, but I get random crashes when I try to call the
"Update" and "Index" routines from my code.  Not sure where to even
start looking for this problem...  Any ideas?  (The crashes happen
*after* my program has relinquished control.)

Should I add Wilbur (as a reference) in my VB code?  Strangely, my
program works even when I don't check the box.  (Why?)

The command wilbur.quit doesn't seem to work, so I wonder if I need to
figure out some other way to check whether the process is running (and
stop it).

The files I'm indexing are part of a Perforce configuration.  Not sure
if that could be affecting things...  We have Dev Studio here at the
office that I could install.  I'm not very good with C++ but perhaps I
could contact the author with concrete info if I had some debugging
tools installed.  Not sure what I would need, though.

If anyone is interested in looking at this program -- which is
freeware and open source -- it's available at
http://wilbur.redtree.com/

(I've just started a new job and if I can get this working I'll be a
hero.  This little app I'm writing could save people HOURS every day.
But I won't distribute anything that crashes all the time.)