Proof at http://support.microsoft.com/?kbid=296773

" WORKAROUND
To work around this problem, do not install more than 192 MB of memory in the computer, or quit some programs before attempting to hibernate.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. "

This is just one of tbe unresolved bugs in this OS. And the article does not tell the issue extends to any of the power saving modes.

Bob