In the "IsDocMatch" function of the rssfeed.xml agent, the doc matches the variable "EventType" the dialogbox gives the parameter as "Event" so you get in the URL "&Event=Error"
So either the function should be changed from :
Dim columnList List As String<br/>
columnList(1) = "Server"<br/>
columnList(2) = "Database"<br/>
columnList(3) = "Agent"<br/>
columnList(4) = "EventType"<br/>
To
Dim columnList List As String<br/>
columnList(1) = "Server"<br/>
columnList(2) = "Database"<br/>
columnList(3) = "Agent"<br/>
columnList(4) = "Event"<br/>
Or the dialogbox should change the URL to &EventType=