I made a few new items in the CK and made sure to get the form IDs from all of them so I could use the console to do the testing on them. I've entered them in correctly (using 01 as the first two numbers since the plugin is second in load order) and I still get the invalid item ID error when I try to spawn them. Anyone know of anything that could solve this issue? And yes, I did save the plugin because I am able to close the CK and load it back up with all of the items still in the plugin file.

The first 2 digits of the ID will change depending on the hexadecimal number of the load order of the MOD ! ( 00 is oblivion.esm items -- 01 I believe would be Update.esm -- 02 would be the first mod .esp to load etc. ) so to use the console you'll need to know where in the load order the mod is loaded (or if you only have a couple mods just keep trying increasing the second digit until it works ( ie 01xxxxxx then 02xxxxxx then 03xxxxxx until it works correctly )

Huh, that did work. I thought it would have been 01 since the only things in the data files were Skyrim.esm and the plugin I made, the update wasn't in there. Must just be hidden. Thanks a lot though, I'm surprised that just changing numbers until it worked didn't occur to me.