when iwant to add a kit to my fifa99
and when iam went to play a match windos return to the desktop and write the massege
"device error"
what shall i do?

Device error normally means that the program is looking for a CD-ROM or floppy disc and gets an error message back.

The best course of action is to un-install FIFA99, re-install it, install SweetPatch MRA, and install the kit into the MRA folder created in FIFA99. This should sort out any device anomalies that might have been created.