Met error when using Loop Refinement protocol

Hi all,
I met an error when using Loop Refinement protocol to refine a loop (I use DS2.1 Win version).This is the error information, as below.Can anyone tell me why I get this error? Thanks in advance!!!
Can't use an undefined value as an ARRAY reference at D:\\Program Files\\SciTegic\\apps\\accelrys\\ds/lang/perl/ProteinModeling/Looper_run.pm line 626.
ProteinModeling::Looper_run::create_amino_incl_file('ProteinModeling::Looper_run=HASH(0xb1a4828)') called at D:\\Program Files\\SciTegic\\apps\\accelrys\\ds/lang/perl/ProteinModeling/Looper_run.pm line 455
ProteinModeling::Looper_run::create_charm_input_files('ProteinModeling::Looper_run=HASH(0xb1a4828)') called at D:\\Program Files\\SciTegic\\apps\\accelrys\\ds/lang/perl/ProteinModeling/Looper_run.pm line 371
ProteinModeling::Looper_run::looper_setup('ProteinModeling::Looper_run=HASH(0xb1a4828)') called at D:\\Program Files\\SciTegic\\apps\\accelrys\\ds/lang/perl/Components/Looper.pm line 198
main:Red FacenProcess
Error calling function
Error during call to function pilot::setup::scriptingOnProcess
PerlScript::HandleError: Pipeline Pilot exception caught
PerlScript::Call: Pipeline Pilot exception caught
CComponentPerlPlugin:Red FacenProcess: Pipeline Pilot exception caught
-> Perl (on Server) - error during Data Record Processing phase
CProtocolStd:Red FacenProcess: Pipeline Pilot exception caught
CProtocol:Red FacenProcess: Pipeline Pilot exception caught
-> Subprotocol - error during Data Record Processing phase
CProtocolRtc:Red FacenProcess: Pipeline Pilot exception caught
CProtocol:Red FacenProcess: Pipeline Pilot exception caught
-> Looper - error during Data Record Processing phase
CProtocolStd:Red FacenProcess: Pipeline Pilot exception caught
CProtocol:Red FacenProcess: Pipeline Pilot exception caught
vcRunComponent:Red FacenProcess: Pipeline Pilot exception caught
vcRunComponent:RazzerrocessData: Pipeline Pilot exception caught
CShortcutComponent:Red FacenProcess: Pipeline Pilot exception caught
-> Shortcut Component - error during Data Record Processing phase
CProtocolStd:Red FacenProcess: Pipeline Pilot exception caught
CProtocol:Red FacenProcess: Pipeline Pilot exception caught
Protocol Run DS Protocol, user Knight: Pipeline Pilot exception caught
Protocol Run DS Protocol, user Knight: Protocol failed: Pipeline Pilot error
Pipeline Pilot Server version 6.1.6.0
Server OS: Windows 6.0 Workstation Service Pack 1