Click the Show/Hide toolbar button on the Standard toolbar in order to
display nonprinting characters. If you find any, such as paragraph
marks (?), indicating blank paragraphs, on your last page, you can
simply delete them.

Note that a table must always be followed by a paragraph mark, and if
that mark doesn't fit on the same page with the table, it will move to
the next page. As a result, if the table is the last item in a
document, you will get an extra, blank page in your document. You can
work around this problem by selecting the paragraph mark after the
table and set its point size to a small value, say 1 pt, in the Font
dialog box.

For more about nonprinting characters, see:

What do all those funny marks, like the dots between the words in my
document, and the square bullets in the left margin, mean?
http://word.mvps.org/FAQs/Formatting/NonPrintChars.htm

See http://home.earthlink.net/~wordfaqs/BlankPage.htm