Attempting to CHECKOUT features from an ArcStorm layer returns the message:
Executing CHECKOUT request...
Feature(s) already locked by another transaction.
There may be additional information in the wservice log.
This message is caused by a non-null value in the lock__id item for the feature, due to either:
1) Feature locking due to another user of the database checking features out for the purpose of editing. The selected features may be locked directly or through topological association.
2) Features locked due to a problematic transaction which was not completed successfully. This could potentially leave features locked but not associated to an existing transaction shown by the LISTTRANSACTIONS command.
Find all locked features to determine which transactions are valid. Release the ones that are invalid.
See, Problem: CHECKOUT returns 'Feature(s) already locked by another transaction.'