Citrix "Protocol Driver" error when launching an application

One of our Citrix Xenapp 5 servers wouldn't allow applications to be launched, giving a "protocol driver" error. After following the instructions on Citrix's web site (http://support.citrix.com/article/CTX108698) and rebooting the server, the server started working again.

Here are the steps I took, in short:

1. Disabled session reliability for the server in the Citrix Delivery Services Console
   
2. Deleted the ICA-tcp connection in Terminal Services Configuration on the effected server
   
3. Recreated the ICA-tcp connection
4. Re-enabled session reliability
5. Rebooted the server

I didn't have to recreate the LHC like the Citrix article says.

Services.exe using large amount of memory

I noticed several of our Windows 2003 servers were performing poorly and found that the process "services.exe" was using between 200 and 400 MB of memory, compared to 6 to 10 MB on servers that were performing normally.

I fixed the problem by simply clearing all event logs. I have no idea why this worked, but it did and almost instantly brought memory usage back down to around 6 MB.