On a newly created Virtualmin gpl installation, with git enabled, attempting to access the created git repository gives the following result:
" Software error: Can't locate object method "startform" via package "CGI" at gitweb.cgi line 409. For help, please send mail to the webmaster ([no address given]), giving this error message and the time and date of the error. "
line 409 in gitweb.cgi is: " print $cgi->startform(-method => "get", -action => $my_uri) .
Changing that to:" print $cgi->start_form(-method => "get", -action => $my_uri) .
" resolves the error and the system behaves as expected.
See similar report here: https://www.virtualmin.com/node/58964