If you've enabled AllowMoreThan50Targets and are not using a program that can handle these extra targets, you may experience very strange behavior in DOS Planets. Note that the UNPACK program that comes with DOS Planets cannot handle more than 50 targets and must not be used if the AllowMoreThan50Targets option is on.
The AllowMoreThan50Targets option (and the related bigtargets command) are almost never needed these days; programs which can display more than 50 targets can usually also fetch them from util.dat (DOS Planets-compatible programs) or kore.dat (Winplan-compatible programs).