There are a lot of instances while working on Siebel integration we use “PRM ANI Utility Service” BS with “GetProperty” method.
The issue with this is when you don’t get a proper hierarchy as expected from the previous step; your Get Property method throws an error message.
 
Usage:
When we have a hierarchy structure and want to extract a property value from that without script.
 
Required Properties:
Input Arguments:
Hierarchy Path - the hierarchical path to reach the desired property (for e.g.: SiebelMessage.Service Request)
Property Name - the Name of the property (for e.g.: SR Number)
SiebelMessage - Hierarchical structure from where we are going to extract the property value
 
Output Arguments:
Property Value - The Value of the property.
 
Issue:
When we are not getting the hierarchy in the desired format, which means the hierarchy path is not retrieved correctly as specified in the Hierarchy Path input argument.
It throws an error stating  “Error Running Method 'Execute'.(SBL-PRM-00104)”
 
Resolution:
In the “PRM ANI Utility Service” BS we can give an optional input argument that will suppress this BS from throwing error and return null when it cannot find the required property.
 
So in the WF Step -> Input Arguments, create a new input argument though it will not be available in the picklist. 
ReturnBlankIfNull      Literal              Y
 
Or if used from script Set the value of this Input Argument property (ReturnBlankIfNull) to “Y”.