powerbuilder - MQ Series problem

[ampra]

i am using Powerbuilder to make an application to put messages in a queue. My MQ Client(version 5.3 beta) is running on Windows XP. i am able to establish a connection with the Queue but am having problems in MQOPEN. The error message says that OBJECT DESCRIPTOR is invalid. The values that i am using are
struc id = "OD "
version = 1
object type = 1
object name = "TARGET.QUEUE"
object q mgr name = ""
dynamic q = ""
alternate user id = ""

please help.