Which browser are you using?
If it is Firefox/Camino browser, type, about
lugins in the address bar and hit enter. It will show you whether the Real Player plugins are integrated.
If it is Safari, goto Help > Installed plugins, which will show you all the installed plugins.
In both cases, if the RP plugins are not listed, you have to check whether RP browser integration is correctly set in RP preferences.
Goto,
RealPlayer > Preferences.. > Internet Tab > Web Browser settings
Here the both items should be checked.
Hope this helped a bit.