I am using FOP 0.20.4 and I seem to be missing the
page number citation value for the last chapter in the
table of contents page. I am attaching my xsl and xml
files.

This appears to be a known bug. Unfortunately, nonbody
yet tracked it down so that it can be fixed. A workaround
is to use
 <fo:block break-before="page"/>
 <fo:block id="{@src}" ...
though this is reported to fail on occasion too. It might
have something to do with content spilling, which deletes
the id form the internal repository during rendering.