It seems that CS-MARS is currently using RDEP protocol to perform the Test Connectivity function to Cisco IDS/IPS devices. Starting in IPS v6.1 RDEP is now disabled by default (it was replaced with SDEE starting in IDS 5.0/IPS 5.1). The reason the functionality of it still worked is that CS-MARS uses SDEE to pull data not RDEP.
The CS-MARS BU has flag this issue and said the fix for it will be released in 6.0.1. As a work around you can just ignore the Test Connectivity button or simply enable RDEP. To enable RDEP do the following:
sensor# conf t
|Issue||Cisco MARS collection failing when using RDEP|
|Legacy Article ID||a44250|