When weird stuff like that happens, it's usually a sign that you need to do a btool clean, or at least a btool -Drefresh=true. I've learned that the hard way just recently.
I just built 18630 and had no problems, but had done a btool clean just before. My executable is 13,140 KB and the whole inkscape folder is 194Mb, which seems to be smaller than your .exe file. I'm using the latest dev libs from the new modevia svn server - see Bob's recent post - http://www.nabble.com/Win32-devlibs-in-Subversion-td17136562.html
Recent updates in SVN have also changed the buildtool.cpp file, so it might be worth deleting that and rebuilding it - g++ buildtool.cpp -o btool
Cheers,
Rygle.
On today's compile of Inkscape (XP, SVN 18630) I got an unpleasant surprise. My system complains: Program too big to fit in memory with inkscape.exe being 224,113,108 B