Looking for Help on Lookups with Related Tables for Access 2010

I bought the Missing Manual for Access 2010 a few days ago to teach myself to use Access. I'm currently on Chapter Five (Linking Tables with Relationships) and working on creating a lookup with related tables. I follow the directions exactly (choosing to get values from another table in the wizard, etc.), but when I get to the end and hit 'Finish' an error message pops up:

"You can't modify the structure of table 'InsertNameHere', because it's already in use by another person or process."

Which is followed by:

"Microsoft Access couldn't launch the LookUp Wizard, or this wizard has been disabled. Rerun the Microsoft Access or the Microsoft Office Setup program, click Add/Remove, and select the Wizards check box. To reenable this wizard, click the File tab, and then click Access Options. Click Add-Ins, and then in the Manage list, click Disabled Items, and then click Go."

After I hit OK on the last error message, it actually creates the Lookup, but it doesn't create the relationship like it's supposed to. I can then go and create a relationship between the fields... but I don't think it's supposed to be working the way it is.

Sorry for the wall of text, just trying to be as detailed as I can. Any ideas on what's going wrong here? I'd appreciate any help! Thanks very much.