Index with QuarkXpress 4 gives strange results

[rcogen]

I just finnished editing a manuscript with QuarkXpress 4 and wanted to compile an index. After completing all the necessary preperation steps I compiled. To my dismay I noticed that the index entries were not is a consistant alphabetical order.

For example, I got the following results:
C
Connector; 30
Check key; 39
Cartridge; 28
air bubbles in the; 60
...
P
Products; 26
Pump; 26
Programming; 54

The attentive reader of this thread will certainly have noticed that the sequential alphabetisation is a bit askew.
I don't understand how this could happen. Can someone help me solve this problem?

Thanks in advance.
Ron