Add lines similar to the following at the top of C:\Perl\bin\ppm.bat (or wherever you have it installed)

set http_proxy=http://<YourProxy Server Address here>:<Proxy Server Po
+rt Here>
set http_proxy_user=<Your UserName Here>
set http_proxy_pass=<Your Password Here>
[download]

Or if that is unclear:

set http_proxy=http://127.0.0.1:8080
set http_proxy_user=shreya
set http_proxy_pass=Proxy_Password
[download]

I hope this helps...