I can't access a provided variable in rule action
I was having this problem with a different module with Rules.  I believe the data types are conflicting.  node:author:name is a string, while the value have calculated is an integer, a decimal or a float. 

My Problem: 

User Field - Voting Currency (set as integer)

Event:


Vote was cast on entity


Action:


Query database for the value of the vote cast 
Calculate the value to add/subtract from the Voting Currency field  
Set the new value of Voting Currency field.


I discovered the vote was a decimal data type.
I removed the Voting Currency integer field with a Voting Currency decimal field and everything worked!