Attilah, these are quite old versions of both the SDK and Carbide. But if you need to develop an app for an S60 2nd edition device this makes sense. I don't have either of this installed currently, so it's hard to diagnose exactly.
You said the SDK is recognized. In the SDK preferences, if the checkbox next to the SDK is turned off then the SDK is disabled. Make sure it's enabled.
One thing you could try is to turn of the "Filter templates based on enabled SDKs" checkbox in the new Symbian OS C++ project wizard.
Also, you could try importing one of the example apps from the SDK to confirm you can import and build the project OK.
If you decide to do any work with 3rd or 5th edition phones then you can get the latest Carbide from http://developer.symbian.org/main/tools%5Fand%5Fkits/downloads/view.php?id=2