<!--exec cgi="/cgi-bin/hitlogger.cgi"-->

You're missing the hash before exec: <!--<bold>#</bold>exec...
When you use the exec SSI, script output is not included into the document. I assume that's what you intend with print "HELLO\n";. For that you need to use

<!--#include virtual="/cgi-bin/hitlogger.cgi"-->

Here's the docs.

There are plenty of log analysis tools out there, though.