Forwarding with proxy

[illdill]

I am using the following configuration to forward website requests through a proxy to another server on port :81

<VirtualHost 192.168.0.12:80>
ServerName

http://www.*denver.com

ServerAlias *denver.com
RewriteEngine On
RewriteRule ^/(.*)$

http://www.*denver.com:81/$1

[P]
</VirtualHost>

Often the site will not respond and show a proxy error in the log:

[Tue Jun 27 11:06:31 2006] [error] [client *.*.117.8] (10060)Unknown error: proxy connect to *.*.186.76 port 81 failed

Meanwhile if I go ahaed and type in http:*denver.com:81 it resolves. The server is working, but the apache server is failing to pass the proxy for some reason. Is it possible this is generating an overload on the proxy?

Thanks