I'm assuming the error referred to Iexplore.exe and that you can't get online.
Search your file system for tbzon1.dll
If you find it in "C:\Program Files\ZoneAlarm" then it's probably safe (anywhere else it is likely to be a virus so ignore all that follows and report back).
I assume you use Zone Alarm firewall. Try "temporarily" disabling ZA then see if you can get to your home page. If you can then get to your homepage, something has probably gone wonky with Zone Alarm and it might have to be uninstalled and re-installed to fix the problem.
How to know you are getting old 5:
A lamp post backs into you