This map crash occurs when map processes empty Time Groups. A common source of empty time groups occurs when users define a Time Group such as:
under the mistaken belief that the wildcard string "BUS<*>" matches FF instances names when in fact it is intended to match FF output net names. This can lead to empty time groups which in turn leads to the map crash in x1_5.21 (M1.5 Service Pack). Time Groups can also be empty if the FFS involved are all trimmed by the mapper.
The map crashed is fixed in version 1.5i. Map will now run successfully and also warn of the existence of empty Time Groups.