First no new users can register including me and have the error "check the errors in the form to continue" with no errors highlighted, multiple passwords, emails etc tested
second issue i cant update to the latest versions since it says ZipArchive class isnt enabled even though i have it added in php extensions
If you edited some of the system files then try merging your custom changes on all the affected files (take in consideration previous updates). That's all the help that I can give to you because I'm unable to replicate your issue neither on the demo or my dev server. Keep in mind that I cannot help you if I'm unable to detect where the problem is and since I don't have access to your server, I cannot determine where is exactly the problem here.
Enabled doesn't mean working properly or working at all. If the system says that the thing is not there is because the class is not there, plain and simple. Regardless of the "on" status, the fact is that at runtime PHP doesn't have that class available and that's all what matters. Refer this to your server administrator, I cannot help you with this.
