If you can do the join manually using arctoolbox tools, simply go to the results window and check the outputs and messages there to ensure that you have all the appropriate parameters specified in modelbuilder. If it doesn't work manually, then the problem is the data and not the tool
Thanks for your reply Dan.
I attempted the join manually and there were no issues. I also ran the model through the model builder window by pressing the run button and there were no issues (the output files are correct). However, the join error still occurs when I attempt to run the model through the dialog window that appears when double clicking the model.