There have been problems reported with SMP systems running LIDS. Many of the problems have been fixed, so it is recommended that you try out the latest version and see for yourself. Xie and Philippe are very dedicated to fixing any such problems, so please make sure to report any to the LIDS mailing list.
UPDATE (2/10/01): Many users have reported success using LIDS-1.0.5 for the 2.4.x kernel on SMP systems.