TDS3012 how to save waveform to PC via GPIB

How can I save waveform on Tektronix TDS3012 to my PC via GPIB ?
I try command: SAVE:WAVEFORM CH1, "C:\TEK\TEK01.CSV" but it does not save.
I try command: FILES:CWD? and it's always shown "fd0:/" and can not make current directory to "C:/TEK"
Please help me to finish my project.
Thanks