When booting Centos 5.5 on a vmbox running on windows XP I get the following message.
Memory for crash kernel (0x0 to 0x0) not within permissable range
This is for CentOS 5.1, you can assume it's valid for 5.5 too
Does the system boot into a useful state? or does the system hang there?
If it boots into a useful state, you can either ignore the message (like I do), or you can allocate some RAM for kdump via system-config-kdump.
If the system doesn't boot, it's rather more interesting.