We were forced to release a 1.3.5 PostGIS upgrade as a result of a bug we accidentally introduced in 1.3.4 during our code cleanup. We apologize for any inconvenience this may have caused people. This bug affects the use of MULTILINESTRINGS and rears its ugly head by giving errors such as invalid circular line string when calling ST_Multi or another odd error when doing a Force collection on a MULTILINESTRING. This hits mapserver users using these geometry types the hardest.

Mas:

http://www.postgresonline.com/journal/index.php?/archives/89-PostGIS-1.3.5-out-the-door-critical-patch-to-1.3.4-and-Testing-Enhancements.html