If you're running 1.03 I'm afraid you'll find a lot of maps won't work in that version. Most are noted that the Coast to Coast Expansion and/or the 1.05 version are required and some note the 1.06 patch are required. Those most likely won't run in your install.
Some maps are not noted what version is required because I didn't know at the time they were added.
BTW! Welcome aboard!