hello i have i think a very similar issue but with RSD component - i can install RSD via ePO but i can't uninstall with the same error you are reporting
if i remotely connect the system where RSD is installed and i proceed to uninstall via add/remove programs it works....
try to deactivate any self protection feature from the products. Check if the uninstall password is configured for DLP Agent. If yes, assign another policy to disable all the protection features and try again.
Also check the Access Protection Logs.... :-P