Rule: Blog Author - Error occurred while processing


I received a system notification saying this:

An error occurred while processing the rule 'Blog Authors' that has prevented the rule from fully processing:

Error parsing Content value '': Must begin with 'C:' or 'T:' in the 'Associated content' option of the Action 'award points'.

Please edit the rule to correct this issue.

What does this mean? I went into the Rule and looked at the dropdown options for 'Associated content', but I don't understand why this error is happening in the first place and what the outcome would be by changing the associated content option.

Please help!