K-PACS server

Can you provide some more details about your scenario? Which of the both is the sender (SCU) of the query? What is your configuration of both (AE title, IP, Port)? Does a C-ECHO (Ping, verify or how ever it is called in your vitrea) work from both?
Keep in mind that K-PACS does not provide query/retrieve as SCP but as SCU, means, you can not make a query to K-PACS. You can only query with K-PACS to another modality e.g. a PACS.