php gtk installation and flex 2.5.4 problem

[admin2]

On ubuntu intrepid 8.10:
while trying to install php gtk 2:
configure: error: Found invalid flex version: 2.5.35. Supported flex versions are: 2.5.4

solution:
aptitude remove flex
aptitude install flex-old

then repeate php gtk configure..
./configure --prefix=/opt/php5_2 --disable-cgi