This issue could occur if Frosty Mod Manager could not access certain files and services due to permission errors, which are essential for the proper operation of Frosty Mod Manager. Solution 1: Tweaking with the Permissions
If the game was launched successfully without mods then try the solutions below. Also, now Launch the game without Mods and even then, if the game could not be launched then you should find the problem with the game and solve it.