Gsx is not asking me where to turn on pushback
This is not necessarily a problem. There are two possible reason for this:
1) The parking you selected has only ONE direction specified in its AFCAD, either "Left" OR "Right", but NOT "Both" so, it wouldn't make much sense if GSX asked you for a direction, if the scenery designer clearly indicated that only ONE is correct!
Of course, you can override the pushback direction by customizing the parking position, as explained in the manual, the chapter dedicated to scenery customization.
OR
2) The scenery designer has specified "NONE" as parking direction, which is different than "Both" (it doesn't mean "Any" direction, it means "None", if a scenery designer wanted to say "Any", he should have set "Both", not "None"), so GSX will only offer you the option for a Straight Pushback.
And of course, you can customize this too.
And i got this error message when im installing gsx i dont know if its related "There was a problem updating some sceneries, please try again later"
Your first problem wasn't a problem to begin with. This one is entirely unrelated, and seems it's caused by your firewall blocking the installation of updated files which are being downloaded while installing.
If you using the very latest GSX full installer, this shouldn't be a problem, but it's best turning off the firewall anyway when using GSX, otherwise you might miss future update and update notifications too.