I don’t know how much can be answered, but I’ll post what I get out of the message.
A “Lock Space Location” operation was requested by job 519359/BD902/BYBYGEKS1 (known because of “The lock holder type is 1.”) The lock request type was <i>Synchronous request</i> because the check was MCH5804. (58 is x’3A’ and 04 is x’04′.) A <i>space location lock wait time-out</i> will be signaled for a synchronous request if time runs out.
See the <a href=”http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic=/rzatk/LOCKSL.htm”>Lock Space Location (LOCKSL)</a> MI instruction topic. Review it for discussion of what the instruction does, and scan for ’3A04′ to find specific mentions of the exception.
But as for what that job was doing…? You’ll have to tell us. Whatever it was trying to do, it ran out of time. In general, it was trying to lock a storage location, but conflicting locks were held longer than this job intended to wait. Whatever is/was stored at that address (storage location) was locked elsewhere for too long, or something very close to that.