So this handover failure condition would it be one of these:
GSM0408
Cause value = 101 No cell allocation available;
indicates that an assignment or handover is unsuccessful because the MS has no current CA.
or
Cause value = 8 Handover impossible, timing advance out of range; indicates that a handover is unsuccessful because the target BTS is beyond the normal range and the target BTS would not accept an out of range timing advance.