Why does the --include switch in grep behave differently when both machines are on 11.10?

I have used the same following commands (in xterm) on two machines of the same ubuntu (11.11-64bit).

grep "jars2deploy" --include=*.xml ./* -r

However, one machine A only search for xml file, as expected, while the other B totally ignored --include switch. I have tried grep --version, which shows grep are of the same version 2.9 as well. My question is how I can config on machine B so the same command searches .xml file.