When u had palringo did you set up an account first? That has to be done prior to loading your other IM services.
But if that doesn't work, the only thing I found searching the web was the UK version that is supposed to be free, heres the link....
http://info.aol.co.uk/aim/wince/index.html or
http://www.freesoftware4all.co.uk/ppc.htm