I used the 'boolprop testingcheatsenabled true' cheat to make my sim know everyone. After that, i used the phone to have her increase her relationship score with a particular sim, namely Alan Raha. Later, I invited him over, but I could not greet or socially interact with him. I also tried inviting him to a party, but once again, I could not interact with him. Finally I tried to ask him out on a date, but he is not present as a potential date. Can anyone help me figure out what the problem is?

http://www.modthesims2.com/article.php?t=74041

Try giving both sims a reset, as described under "alternate method" listed on that link there.

Thanks, but no luck. Any other ideas?

If you have any hacks, one of them might be conflicting with the cheat. So backup your entire My Docs/EA Games/Sims2 folder. Then move your Downloads folder to your desktop. Test the game to see if your sim can interact with the other one. Also, please look at the rest of this FAQ.