How are you trying to convert the document? These are a 3 different things I would try:
#1. try - file, save as - then save the WordPerfect doc as a MS Word doc.
#2. try - open a new doc in MS Word, then Insert ? File.
#3. try - Cut and Paste.
I use #1 to save extensive WP tables into MS Word with no problem.
Back up first, eh.
🙂