A vacuum leak is possible and a good place to check first before replacing parts. You can replace those parts as preventative, but definitely be sure to diagnose the issue. Doing a quick search on our forum, I found this thread where the individual has 3 of the codes you have:
http://forums.pelicanparts.com/porsche-996-997-991-forum/930729-996-3-4-fault-codes-p1124-p1126.html. Not much, but some info for P0150 here:
http://forums.pelicanparts.com/porsche-996-997-991-forum/930093-p0150-codes.html. Let us know what you guys find out.