strange table behaviour

Hi all! I have no idea if this a portable openoffice or a general openoffice problem - but I'm experiencing some nasty lil problems when working with tables, especially in documents previously written in MS Office. I had do some work on -until now - 2 .doc files that had tables in them. Worked, saved - and WHAM - when opening the documents, my clients complained about tables intertwining. When I opened thjem again myselves, some thing had gone very, very wrong. It seems that openoffice saves everything in a strange way, and nothing is the wy it was when I saved the documents first. Anyone here with similar problems?
Thanks