[imp] Enabling cookies

[Don P]

Running Horde 2.0, Imp 3.1 on PHP 4.1.1. on Windows 2000 IIS 5.0.

I've been running IMP for quite some time without cookies (not on purpose). The 
webmail server was hacked via session info in the URL so I'd like get session 
cookies up and running.

I've searched the archives, FAQ and docs to no avail. I see folks talking about 
disabling cookies but not much about enabling them. 

Can somebody provide or point me to info on what I should check/tweak to get 
cookies working. The browser has cookies enabled.

Thanks.