design compiler tcl mode 's error

hi members,there are such errors when I invoke the dc_vision -tclmode.
What should I do to eliminate the errors? thanks


Error: Cannot create procedure named 'group_variable' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'group_variable' cannot be modified. (CMD-051)
Error: ::group_variable
Use error_info for more info. (CMD-013)
Error: Cannot create procedure named 'print_variable_group' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'print_variable_group' cannot be modified. (CMD-051)
Error: :rint_variable_group
Use error_info for more info. (CMD-013)
Error: Cannot create procedure named 'read_verilog' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'read_verilog' cannot be modified. (CMD-051)
Error: ::read_verilog
Use error_info for more info. (CMD-013)
Error: Cannot create procedure named 'read_vhdl' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'read_vhdl' cannot be modified. (CMD-051)
Error: ::read_vhdl
Use error_info for more info. (CMD-013)
Error: Cannot create procedure named 'read_db' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'read_db' cannot be modified. (CMD-051)
Error: ::read_db
Use error_info for more info. (CMD-013)
Error: Cannot create procedure named 'read_edif' - existing command
Use error_info for more info. (CMD-013)
Error: Procedure 'read_edif' cannot be modified. (CMD-051)
Error: ::read_edif
Use error_info for more info. (CMD-013)

None meets the same question?
Could anyone give a suggetion?