Looks like there is a corrupted version of nbtenum.exe in BT4.R2, as shown below:

root@bt:/pentest/windows-binaries/tools# wine nbtenum.exe
wine: Bad EXE format for Z:\pentest\windows-binaries\tools\nbtenum.exe
root@bt:/pentest/windows-binaries/tools# ls -al nbtenum.exe && md5sum nbtenum.exe
-rw-r--r-- 1 root root 180 Dec 16 2008 nbtenum.exe
8718f3a78cf149db51566424ca1a608c nbtenum.exe


rest of PE files are working fine.
Thanks