@stuartyager4437
That is typically a php notice related to numeric arrays. It will unfortunately take a lot more than what you posted to figure out your true issue. You'll want to go to line 425 in your code as see what is being passed or executed.
If you have code that runs programming loops that output html (probably don't have this) then it may be something other than line 425 (i.e. it may be line 475, etc.). Also, I am not completely certain that this undefined offset has anything to do with your cancel function not working. Typically when you get a notice your code will execute anyways, so it's possible your issue is elsewhere.
