When you installed the hotfix, the instructions had you create an advertisement to distribute it. Did you instruct it to install on machines you remote control to and if so, can you verify that it did install? The new client version should be higher than 2.50.2726.0018, which is the RTM version. My version is 2.50.2726.0102 but this may vary depending on additional changes made to the hotfix.
I think the main problem is in the client/server you're remote controlling to, not the initiating client.
You may need to restart the agent and remote control services also.