Changing theme results in PERL Error, system is inaccessible

I have WebMin and VirtualMin installed on a Ubuntu 8 64 Server. After changing the theme through WebMin, I receive the following error:

HTTP/1.0 500 Perl execution failed Server: MiniServ/0.01 Date: Thu, 30 Oct 2008 16:18:29 GMT Content-type: text/html Connection: close
Error - Perl execution failed

Undefined subroutine &main::get_left_frame_width called at /usr/share/webmin/virtual-server-theme/index.cgi line 83.

This has made the system completely inaccessible, hence the critical status. Thanks!