You do not need the clockrate interface command, though that is not your main problem. The clockrate command is needed only for synchronous serial V35 or RS232 interfaces.
The line code errors might indicate that the T1 transport equipment is set for AMI linecoding. Try changing the router settings to AMI and SF framing. AMI is seldom used today, and limits usable bandwidth to 56kb per channel.
service-module t1 linecode ami
service-module t1 framing sf
Your wiring might still be the problem. A T1 signal is very robust, and crossed pairs or broken wires can result in linecode and path code errors.