By default the Maximizer files are stored in c:\program files\maximizer\maxdata\addrbks, or possibly in c:\maxdata, generally this depends on if you have a client/server installation or a workgroup installation.
If you cannot find the files in either of those locations you can search the disk for *.max files, the .max files are the Maximizer data files so you should be able to find the address book files that way.