I don't have much info on Gulf-Stream but I would check the following, make sure the parking brake is set, the engine is in park and make sure all the storage compartments are fully shut, I have seen some manufactures will use a inner lock if the storage doors are open that will cut power to the slides, this is to prevent damage if the rooms go out and the doors are open.
Check both your house battery and chassis battery voltage as well. IF you are unsure of the fuses get a 12 volt test light, most auto parts stores have them for a few dollars, turn the ignition switch ON and probe each fuse, I suspect you are going to find a fuse or breaker outside for the rooms, could be near the batteries OR in a battery control box. Probe each fuse for power with the test light, some items will only have voltage when the ignition switch is ON. Also look for a breaker that might be tripped below is a picture, as a general rule they like to stick them 18" from the batteries and can be on the chassis frame or inside a battery control box. If you use a test light you should have voltage on each post, if one post does not have power it is the problem, most breakers will have a tiny tab on them that pops out when they trip...
The other issue is if you had a slide-room controller issue for the rooms, that normally is between the switches and motors. IF you happen to know the manufacturer of the rooms I might be able to have some more input for you.
My goal is for you to be satisfied with my efforts, only select a STAR rating if you are satisfied. IF you would like to try another expert please let me know....