Unhelpful error message, when colon is used in wrong place

[csnyulas]

Reported on the mailing list:
http://protege-project.136.n4.nabble.com/Error-while-executing-Cellfie-rules-tt4667474.html

The problem is that the user wrote:

Individual: @A*
  Facts: says_Hello: @B*

instead of

Individual: @A*
  Facts: says_Hello @B*

(observe the extra column after says_Hello)

The error message "Missing required prefix" does not contain enough detail to realize what the problem is. If we would include the name of (what Cellfie think is) the missing prefix (in this case "says_Hello"), it would be helpful to locate the source of the error.

[csnyulas]

Here is another case where the unhelpful message prevented the user from easily identifying the problem (which this time was in the data, not in the rule):
http://protege-project.136.n4.nabble.com/Cellfie-Individual-Import-Problem-td4672052.html
Here is the direct link to the message identifying the cause of the issue:
http://protege-project.136.n4.nabble.com/Cellfie-Individual-Import-Problem-tp4672052p4672066.html