DotNetNuke.Security.Membership.MembershipProvider p = DotNetNuke.Security.Membership.MembershipProvider.Instance();
UserInfo user = p.GetUserByUserName(0, "myname", true);

I get the following exception:

Exception: Absolute path information is required.

I have debugged the code and this is happening in FBCachingProvider class during cache setting.

Also, I have the following in my web.config file as well:
<caching defaultProvider="FileBasedCachingProvider">
<providers><clear/>
<add name="FileBasedCachingProvider" type="DotNetNuke.Services.Cache.FileBasedCachingProvider.FBCachingProvider, DotNetNuke.Caching.FileBasedCachingProvider" providerPath="~\Providers\CachingProviders\FileBasedCachingProvider\"/>
<add name="BroadcastPollingCachingProvider" type="DotNetNuke.Services.Cache.BroadcastPollingCachingProvider.BPCachingProvider, DotNetNuke.Caching.BroadcastPollingCachingProvider" providerPath="C:\Projects\SVN\ResponseElement\branches\dev\SystemCenter\main\DotNetNuke\Library\Providers\CachingProviders\BroadcastPollingCachingProvider\"/>
</providers>
</caching>

I would appreciate any ideas or feedback.

Thanks,
Paria