OK couple of questions:
1. Does the database ALREADY exist on the test server?
2. If so, does the directory structure where the MDF/LDF match where the MDF/LDF reside on the live server. In this I mean if the files on the live server were located in the C:\MyDir\Data folder, do they also reside like that on the test server?
IF NOT ... you need to use the WITH MOVE option to place the MDF and LDF in the folder(s) that are being used on your test server. If you are using the Restore wizard, you need to change the file path on the Options tab of the wizard. Change the path in the "Move to physical file name" option to the desired location.
Thanks
J. Kusch