Emu XL-7 & MP-7 User's Group

what's happening here?
today I turned on my xl-7 and many of may patterns was corrupted. may
traks are not correctly assigned to its preset. Insted of the name af
the right preset,a message says (not installed).
Moreover, if I re-assign the right preset to the track, and then save
it again, this assignement go lost when I recall the pattern!!
I've tried to save the preset to another location, to save the patter
to another location, to move the track to another track number without
success.
plese help me, I fear that all those tries with sysex uploading has
caused some damage to my machine and to my work!

davide