What sub-format of Word document does Pages use for export?
I just tried this out – The following happened.

WRONGE way:
Open a new document in Pages, File -> Export To (Word..) -> Advanced Options -> Choose .docx format.
LibreOffice crashes everytime I try to open the file.

RIGHT way:
Open a new document in Pages, File -> Export To (Word..) -> Advanced Options -> Choose .doc format.
Then it opens fine in LibreOffice. 

NOTE: This was tested in Pages version 5.0

PS: Didnt see the post before me. Sorry about that.

PPS: It seems you are trying to open a specific format, but the problem is really the way you export it in the first place. Please write if you can't export in .doc format.