PS1.6 "Validation function not found. isIsbn", products not opening on page (Error 500)

[WSParts]

Hi,

 

I was having issues with setting impact on price in a product combination whereby in the back office if I changed the impact on price and saved it, it would not change in the front or back end. Changing impact on weight would make a difference, but price would always be £0.00.

 

Following the instructions here, I replaced products.php and productcontroller.php with a master copy ( didn't save original files) and the issue persists. It has also thrown up a different issue whereby whenever I try to save or delete any product combination, I get shown an error "Validation function not found. isIsbn" at the top of the page. I have attached screenshot. Also now I have discovered that while the home page loads products and you can search, when you click to open them it gives Error 500.

 

Can anyone please help me with relation these issues:

1) Impact on Price not updating when changed in back office.

2) "Validation function not found. isIsbn" at the top of the page. 

3) Products giving Error 500.

 

The website URL is wsparts.co.uk incase anyone can find any other issues at play.

 

Thanks,

DT

Edited July 11, 2018 by WSParts
additional info (see edit history)