Check that the permissions of the directory and files look exactly like the following -- incorrect permissions will disable a StatupItem[sic] (10.4 only?):
drwxr-xr-x 4 root wheel /Library/StartupItems/logintext/
-rwxr-xr-x 1 root wheel /Library/StartupItems/logintext/StartupParameters.plist*
-rwxr-xr-x 1 root wheel /Library/StartupItems/logintext/logintext*

It seems rather odd that a property list file would require execute permission since it cannot be executed by the shell. Are you sure this won't work with the permission set as shown below?

-rw-r--r-- 1 root wheel /Library/StartupItems/logintext/StartupParameters.plist

I didn't try that, but you're probably right. I know that the directory and the script itself needed exact permissions, so I just did a "chmod -R" for everything.