Your first screen shot isn't showing errors. These look like the "receiver ready" messages that are continuously sent back and forth in order to verify the PRI is up. You are seeing them because of a configuration option you have. If you go under SYSTEM CONFIG and go into EVENT LOGGING you can set "ISDN L2 MESSAGES" to MINOR. It appears to be at INFO right now. The "L2 MESSAGES" displays the raw, hexadecimal D-channel signaling.
The "ISDN L2 FORMATTED" can be helpful but gives a lot of information. The "L2 FORMATTED" does not show the receiver ready messages but it does give the complete ISDN Layer 2 messages.
Your second screen shot doesn't show enough information. It shows the ATLAS sent a RELEASE and received back a RELEASE_CMP (release complete), and the last part at the bottom of the screen shot shows a USER_BUSY message which I'm assuming was sent by the ATLAS. All the messages in this second screen shot are on Ntwk 1.
So the question is whether the ATLAS sent the call to "5178" to the correct PBX and if the PBX responded with the USER_BUSY or is there is something else going on.
If you have a Syslog Server available to you, I suggest setting up the ATLAS to transmit the event log to the syslog server. You set this up under SYSTEM CONFIG in SYSLOG SETUP by setting the TRANSMISSION to ENABLED and setting up the IP address of the Syslog Server.
You may be able to get an idea of what is going on through the ATLAS with only SWITCHBOARD and ISDN EVENTS set to INFO and everything else set to MINOR.
Hope this helps,