Here are the steps I followed to resolve it:
The first thing I did was to rebuild the service data source
Select HPD:Help Desk, then click Create Filter, that should rebuild the data sources (work-flows)
This didn't work, then I went to SLM:RuleACtionSetVAlueItem and Rule Definition (SLM:RuleDefinition) forms and clear all HPD related records, then tried to rebuild the data-source.
This didn't work either, then I checked if the SLM plug-in is running properly and not crashing. This can be done from Task Manager as shown below. I tried killing it several times and restarting it, but this didn't work. can kill it and it will be restarted by arplugin.
But when I checked the Application Pending form and there were lots of BR-BRIE records. I cleared all these records but none of the above steps were working. The last one I tried is to check if SLM is suspended (Business-Rules-Engine-Suspended set to T) and indeed this was disabled. When I change this to F and tried to rebuild it worked.