What to do about messages about corrupt tables in Microsoft word

Hello,

I am receiving message that I can't create or save tables in ms Word 2003. Many different messages. Intermittent problem but I can't count on any of my work taking hold. File attached shows several of the messages. This a a computer running Windows XP and it's on a home network with a MacBook and an HP J4680 Al-One Network printer. Previously I have encountered messages saying I couldn't open certain old files because they were too old a format. HOping the attached file will cause someone to recognize what's going on. My virus protection hasn't found anything. Unfortunately the error is intermittent. I just tried to make it happen to a file so I could try saving it to a flash drive instead of my hard drive but now the error isn't appearing. I'm sure it will be back though. any guidance would be appreciated. I'm afraid to back up my drive. I do have one new piece of software: ReadIris Pro 1. Don't know if that is related.