Error when converting task to sub-task

[Julia Cameron]

Whenever I try and convert a task to a sub-task of a different task (of the same type as the first in this case) I simply get an "Opps - an error has occured".

Does anyone know what is causing the problem?

Looking at the get help page the following is in the log. Cannot fit the entire log in here.

com.atlassian.greenhopper.manager.lexorank.LexoRankIntegrityException: Expected exactly 2 rows; the maximum marker row and the lowest ranked row for rank field[id=10005]

[Julia Cameron · Accepted solution]

After the same error occurred when deleting a task I searched for that error and came across this potential fix.

Several actions such as issue ranking, move, export are failing 

Following the suggestions in that page has fixed the conversion error that we were having.