In a Galaxy S with GB and Semaphore(CWM 126.96.36.199), if you flash the Uninstall zip before flash Crossbreeder 2-24-13, it fails due the incorrect mount command. It seems that this recovery needs the complete mount command (mount $dev $folder) , maybe recovery.fstab is missing? I don't know...
I can't did some test because there's not adb access in this recovery, but looking in a custom rom for this pda I found that the correct command is:
run_program("/sbin/mount", "/dev/block/stl9", "/system");
In fact, /system is mounted by default by the recovery, but the uninstall process unmount it and crossbreeder can't mount it again, ergo crossbreeder install process fails.
Flashing uninstall, reboot recovery and flashing crossbreeder works flawless.
Flashing uninstall, "mounts and storage"->"mount system" (it appears unmounted) and flashing crossbreeder works flawless.
A workaround to prevent this specific problem could be build an all-in-one package for Crossbreeder, where the install package firstly uninstall previous versions if exists, then install the new version and unmount all at finish; and let the uninstall zip only to be used for definitively remove crossbreeder.
I don't have the handset to do further testing , sorry.