unless you're sure you installed gapps ther's nothing additional to set up. You sure you have enough space ? - What's your partition size? otherwise i would try the following: either factory reset from settings menu or else do a full wipe + dalvik, reflash rom + gapps
I'm having a similar problem, I tried withe the 15mb gapps by konstaKang, did everything as per the instructions but not even the native browser worked. I then factory reseted the phone,wiped all the data system+sd, partitioned sd with a 264mb ext partition with a 128mb swap. did the install again followed by gapps still nothing.. no play no chrome no(failed) native browser.
I redid the process several times more with gapps-ics and gapps-jb from goo.im both of about 83mb, but nothing..
I had CM7 prior to trying this.