This mod probably changed your resolution settings Lock On graphics.cfg file.
A work a rounds is to;
1.Run Modman and uninstall the mod.
2.Using Modman read the readme file of the mod to find the screen resolution settings for the mod. If there is no reference to the screen resolution settings, open the graphics.cfg file within the mod with located in the Cofig folder.
Look for the following info:
DisplayMode
{
resolution = {1024, 768}; ß write this down
bpp = 32;
fullscreen = 1;
aspect = 1.333333373;
Interface
{
resolution = {1024, 768}; ß
bpp = 32;
fullscreen = 1;
aspect = 1.333333373;
}
Simulation
{
resolution = {1024, 768}; ß
bpp = 32;
fullscreen = 1;
aspect = 1.333333373;
}
AVI
{
resolution = {640, 480};
fullscreen = 0;
aspect = 1.3333;
3.Run Lock On and change the screen resolution to match that of the mod.
4.Close Lock On and re-install the mod and run Lock On again.
This is one way, hope it help. The same happened to me and I ended up re-installing Lock On.