@Vintage Well, as suspected: I'm a big dummy. I just re-launched Blender and it worked again. Thanks for the help!

So i tried to export a file using the SMD tools to export an .smd file. It only gave me the option to export in .dmx so i tried to uninstall the add on and re install it. (Thinking it'll help) Once i did, however, i tried to activate the add on via the User Preferences menu in the Add on tab and it gave me this error:

Traceback (most recent call last):
File "C:\Program Files\Blender Foundation\Blender\2.71\scripts\modules\addon_utils.py" , line 299, in enable mod =_import_(module_name)
File "C:\Users\user\AppData\Roaming\Blender\2.71\scripts\addons\io_scene_valvesource\_init_.py", line 48 in <module. if mod: imp.reload(mod)
File "C:\Program Files\Blender Foundation\Blender\2.71\python\lib\importlib\_init_.py" , line 144, in reload methods.exec(module)
File "C:\Users\user\AppData\Roaming\Blender Foundation\Blender\2.71\scripts\addons\io_scene_valvesource\export_smd.py" , 29, in <module> importError: Cannot import name 'datamodel'

It may be that i'm just a big dummy, but i don't know what to do and no one else seems to have this problem. Help?