Its possible you are using models from another game that isn't mounted into gmod. Other than that, maybe you are using the wrong prop type for the wrong prop. When you post the compile log i will have a better idea.
Make a spray in photoshop, import it to vtf edit, make a vmf and vtf, paste those into the materials folder of your chosen game, make a brush or decal with that texture, and then use pakrat to include it in the bsp.
Realistic looking 3d skys for your new map -- http://developer.valvesoftware.com/wiki/Di...levation_Models You basically take a real area, and convert it. Havn't tried it yet, but it looks awesome.
Upload it to www.filefront.com or www.rapidshare.com Depends which game you compiled it with. Css -- steam/steamapps/username/Counterstrike/css/maps gmod -- steam/steamapps/username/garrysmod/garrysmod/maps HL2:DM steam/steamapps/username/hl2/hl2/maps You get the idea.
Takes a while to rip the code so as it works in the timer system, from past experiance (Join Killa's) It took him a good few hours testing it and ironing the bugs out.