There are major issues introduced with the version 4.0.17. I have been able to overcome them with the installation of 4.0.18, I suggest the version be incremented ASAP. These issues will become apparent if a text variable is stored with spaces at the end and the field is indexed which happens in most applications where data from external sources is not trimmed. This may account for up to 30 percent of the bug reports I've seen filed. ref. http://www.mysql.com/doc/en/News-4.0.18.html
bumped 4.0.18 to same stable level as 4.0.17, strongly recommended that ppc/alpha move to 4.0.18 as well