"READ THIS! This isn't really a bug, but when you go to tow the car, you must get in and out of it before you are able to tow it. The car is un-towable until you get in and out of it, and having the player get in and out of it is the only way I could find to make the car towable."
We can just pretend CJ goes in to unlock the brakes or something just so the car becomes towable. Do it the imaginative way ;p
You do not have to press a button to tow the damaged car. You must first get in and out of the car to allow it to be towed. Then get back in the tow truck and make sure you have the towing arm all the way down. Then you should be able to tow the car.
About the mission not starting when you enter the red marker, I think maybe you forgot to put the mission script in your CLEO folder so make sure you followed the installation instructions exactly. If you do have all of the scripts in there and this is still happening, please let me know.
I'm not sure how to make mods compatible with SAMP as I have never used it and have no experiance with it. About the car not appearing, did you download the most recent version? I know this bug was occuring in the first one but I thought I fixed it in the second. If it is the most recent version that is still doing this then please let me know and I will try to fix it.
I did mention that bug in the readme file and in this mod's description. You have to enter and exit the car in order to be able to tow it. I think removing references to the car did allow it to be towed, but it created problems and crashes later, so getting in and out works better.
That's a good idea, but part of the mission is attaching the car and then making sure it stays attached as you drive it back to the garage. For this to work, it's easier to just use the towing method the game already uses.
You need to add a time out to the ending cut scene where the customer picks up his car. the AI in SA has always been just a wee bit below the retarded line and often times the customer will get stuck and not drive away with his car leaving you with a permanently frozen game. in fact it is safer to just get rid of the cut scene camera all together and end the mission immediately when he enters the repaired vehicle