Diagnose MS Word's for bottleneck(s)

Question

When merging two different Word documents I sometimes get really odd errors. Sometimes in the error message is stated, that a font is missing, sometimes - "insufficient RAM or disk space", sometimes - something like "Unspecified Error, word/document.xml, Line:2, Column: 0". This prevents in creating a merged document. What is really strange here, is that this a) not always happens and that b) each an every of these documents I try to combine can be opened on its own. I also have lot's of free disk space and according to task manager when these error messages come, only about 3-4 GB of available 16 GB RAM are being used. Other relevant specs are: Win7 x64 and Word2010 both x64 and x86 editions.

So I need to investigate these anomalies and my questions will be: 1) what could most most likely cause these error(s)? and 2) what possibilities are there to monitor what exactly happens with Word, when these error messages appear?

Huge thanks in advance!

Answer 1

One possible approach that I've found so far is to monitor loads by using the Process Explorer. A thorough explanation of loads and their limits is given here.