ASP file double-entries' into SQL server

This really confuses me, I have an ASP script that updates an SQL server upon receiving form parameters and the results seem to be of a system performance nature vs. a programming mistake.

I have a nested loop behavor as elaborated below:
1. form submits number of products (ie. 2 types)
2. also submits number of cartons/product (ie. 1 each)
3. in the SQL insert result, there should be 2 products with 1 box each (as above)
4. but what happens is that sometimes, it's correct... (2 types, 1 ctn each); but sometimes, it's double! (4 types, 2 ctns each)!!!

When I use Netscape to process the form and script, everything works fine (always!) but when I use Explorer (which is the client-requested app), sometimes it works and sometimes it doesnt! What's the difference between the two and why would it work ALL THE TIME in Netscape and only SOMETIMES in Explorer?!

I can email you an example of the form then the processing script as I can't paste them here.

Any help would be highly appreciated! Maybe even a token of my appreciation would be in order just to get real help.

Thanks in advance, JM.