Had a LS member with a similar problem that turned out to be a faulty stick of RAM.
Courtney 75RDM/75BST/75BLU/61WHM Quetzalcoatl "For future reference, anything as big as a house tends to aggro." Caia. "I keep getting annoyed that I damage slowly for small damage, and my WS feely sucky." RDM mellee in a nutshell!