New: i found 2 ways to fix this
1. make a backup of the player a_dat file in the gtadata folder and replace it every single time before the game is started
2. you can also fix this problem by right clicking on the player a_dat file in the gtadata folder, click on properties and going to the security tab
click on system in the users list and deselecting the "modify" checkbox.The only problem with this method is that the game will crash if you try
to change the name of a player, and if you try to leave the level.Thus it does not allow cheats.
Unfortunately neither of these allows the game to be saved so #1 is probly the best option if you want to get to the other levels.
Edited by Strike9, 30 May 2009 - 08:41 PM.