AB0117 - Activity libraries must be valid
Processes, Scenarios, and Activitiy Libraries themselves can reference Activity Libraries containing reusable user-defined activities. This rule will alert you if a library file contains invalid information that is preventing it from being properly loaded.
This error is typically related to poorly formatted XML data in the file and might be the result of a bad merge from a version control system. The error message will provide an indication of the actual problem with the file, such as line number or column (i.e. position) on the line. Open the library file in a text editor and correct the invalid XML formatting.