computer locked up on libre office

I know my topic is off center, but it is affecting my business and maybe someone can help. There are three computers in our office that use files created in libre office. The files allow us to calculate a customers requirements so we can create an order. Two computers are PCs running W7 and I have a MBP running Lion.

One of the staff emailed me a file and said he couldn't open it, his machine hung up. I tried to open the file and my machine hung up. The third guy tried to open the file and his machine hung up. Bad file, right?

Well, i then tried to open an older copy of the file that was perfectly good. It would not open - hung computer. I tried numerous files of different subjects. Many would open, most woud not.

I deleted the LO user profile and reloaded Libre Office. Files hung up.

I went to Time Machine and downloaded an old version of the file, then copied it, then tried to open it. Hung up.

Now I am thinking that Java may be corrupted, since Libre Office runs on top of Java. I don't know how to reload Java.

BTW, the PCs are having the same problem.

Any thoughts?