Hmm...another one with this problem eh?
First question, have you definitely installed the correct 1.51 patch? There were two or three beta versions before they finally released one so make sure you got the right link!
If you have got the right one and it didn't work, then uninstall First Strike.
With FS uninstalled, make sure the FS launcher is uninstalled as well.
Now reinstall First Strike, during its installation the launcher program will pop up asking to install, do not click yes. Just leave it, move the window until First Strike has completely installed, then click yes to install the launcher.
Now do the usual update process etc and hopefully it will work. If not, try the rename 2142 exe thing.
The important thing here for deluxe users, seems to be that it does not like installing the launcher and FS at the same time.
Bite my shiny metal Tie Fighter!

