help with 404 error

[sai_sevak]

I just saw the following errors for the first time in 3 months (since my site went online) in my error log:
POST /cgi-bin/contact_us.cgi HTTP/1.0 404
POST /cgi-bin/formmail.pl HTTP/1.0" 404
POST /cgi-bin/contact.cgi HTTP/1.1" 404
POST /cgi-bin/mailform.pl HTTP/1.0" 404

Could someone please guide me as to what could be the possible reasons?

Any help would be appreciated.

[uncle_bob]

It's likely just zombied machines looking for systems with vunerable formmail installations that can be used for spamming. Most websites get these entries every once in a while. As long as you don't have formmail, or anything like it, you should be fine as your webserver will just return 404's

[sai_sevak]

Thankyou very much for your response. I appreciate it.