I agree the profile information is confusing but the a1103 is a G4. http://www.everymac.com/systems/apple/mac_mini/specs/mac_mini_g4_1.25.html
Do you have a bootable backup drive? Without that or without a boot disc you are strongly disadvantaged. There are ways you can attempt recovery but they are not simple.
If you don't have an installer disc available you can try effecting repairs using fsk in Single User Mode - http://support.apple.com/kb/TS1417
Post by japamac about using fsk - http://discussions.apple.com/thread.jspa?threadID=1649143