Hey JA-tek,
It appears that you're having a problem using Safari on your iMac on OS X El Capitan. You keep getting an error message related to webkit, and we're glad to provide assistance.
If Safari isn’t working as expected or a web page doesn't open - Apple Support -- See if the steps in this article helps.
How to use safe mode on your Mac - Apple Support -- If you're still receiving the webkit message, restart your Mac in safe mode. After done with testing, restart your Mac normally. If it didn't happen while in safe mode, see if the issue's resolved after restarting normally.
Please be aware: "When you start up in safe mode, your Mac prevents some software, such as startup items, from loading, and it performs a check of your startup disk. Your Mac may take longer to start up because of the check."
Let us know how that goes.
All the best.