FYI for anyone else having these issues on a 4.2.* install, I think I fixed them myself.

The first error is corrected by replacing the deprecated functions & syntax in 330 and 397:
Line 330: Line 397: The second error is corrected by replacing with this context in line 275 and 416:
and setting default values in lines 241 to 246 as this: NOTE: If you delete values from the pricing the code will error out, but it actually still functions correctly. The solution is to always put "0.00" instead of "" in the fields. Someone who knows PHP better than I could probably write something quick to replace the null value when it's passed. I tried it quickly and had no luck.

I AM NOT A CODER - DON'T ASK ME HOW TO FIX ANYTHING ELSE. I'm a hack at best.

Will this work on 4.2.2 ???

Hi I am using vBulleting 4.2.5 and tried doing a test checkout using CartPlog. But it seems Add Cart button is not working properly because when I add the product in cart, it updates to zero product in cart. How to fix it?

Uninstall and try:
https://vbulletin.org/forum/showthread.php?t=246427

Probably the lesser of the 2 evils...