Well, I have a bunch of mods and plugins for Morrowind, but when I check the box and go to areas where they're active, I get an error message that it can't run the file. If it makes a difference, I installed them all at once before running the game with them, and also tried taking all but one out to see if that would work. It didn't. :brokencomputer:

EDIT: the message says, "Model Load Error: (file name pertaining to plugin, usually lists all files) cannot load file in (same file name) Will use the default object Marker_error.NIF. Continue running executable?" And it's not exactly a crash, you can keep playing but it replaces certain things with giant yellow exclamation points, which I assume is Marker_error.

Which error message? What does it say?

Post the contents of your Warning.txt following a crash.

Then you have installed the mods incorrectly.
The esp cannot find the meshes it needs from your Data Files folder.

The pinned threads has a http://www.gamesas.com/index.php?/topic/106063-morrowind-mods-faq/page__p__1772866#entry1772866.
Also check the 'ReadMe' file for any special instructions... but the pinned thread info is the most clear and concise.

And if you're on Vista or WIn7, make sure you http://www.gamesas.com/index.php?/topic/781497-vistawindows-7-problems/page__view__findpost__p__11352753. (this will prevent many problems)