Previously, server based BizTalk adapter was used to access MQ Series and that requires MQ series server on Windows as intermediate server between BizTalk Server and non-Windows Queue Managers. In some situation, when installing the MQAgent to Windows MQ Series box is not an option the client based BizTalk adapter (MQSC) is needed to achieve the same goal. 

MQSC is not part of BizTalk bits but it can be found in Host Integration Server 2006.

While setting up MQSC adapter, here are some of the tips when authorization issues occurred (Thanks Tom Canter on this):

1. If MQSeries server box and BizTalk Server box are in the same domain

• Configure the MQSC receive/send adapter using a host instance with domain account as logon account
• Add this domain account to domain security group: "<YourDomainName>\Domain MQM"

2. If MQSeries server box and BizTalk Server box are NOT member server of any domain

• Create a username on both BizTalk Server box and MQ Series server box with identical username and password
• Add the above created account into local group "mqm" on BizTalk server and MQSeries server
• Configure the MQSC receive/send adapter using a host instance with the above created username as logon account