Did you install this using the install.pl script? The '/u01/etc/routers2.conf' error indicates that you still have the default values in the configuration, which are automatically replaced by the install.pl script. It is possible that you installed it in a different way previously, or unpacked the package in the cgi-bin directory.
It also sounds as if you may have the infamous IIS bug (IIS does not support the standard CGI interface correctly) and so you may need to set the 'myurl' setting in the routers2.conf to point to the correct full URL of the routers2 script to get around it.
http://localhost/cgi-bin/routers2.pl is probably the correct URL to use, if you have IIS. The .cgi extension is for all other web servers (eg Apache) but IIS, as usual, needs special treatment.
Look in c:\scsmrtg\rrd-data for routers2.conf (or wherever else you chose to install it) and edit this to set 'myurl =
http://yourhost/cgi-bin/routers2.pl' (change yourhost to your hosts fully qualified name of course) and this should fix the problem.