QUESTION:

How can I increase for a product the number of related products, sections a product can belong to and price options?

ANSWER:

To do this you need to edit in /admin/inc the files addprod.asp and showproddata. There is parameter for each option at the top:

'General constant declaration
nMaxPriceOptions = 5 'Maximum number of Price Options allowed per product
nMaxRelProds = 6 'Maximum number of Products Related allowed per product
nMaxSections = 5 'Maximum number of sections allowed per product