Norton presence during bootup

I had to uninstall Norton IS 4.1 for work-related reasons, but when I boot up my Mac (using Command-S option), I see several  references to Norton kernel extension (com.symantec.kext,ips).  It seems like my Mac is still trying to load this kernel extension even though the program has been removed, and I'm getting the error messages during boot.

 

Is there  a way to disable this or eliminate the error?

 

Thanks.