Get error message "The filename, directory name, or volume label syntax is incorrect." when run mbdbmaint.exe in windows

Install membase server 1.7.0 on windows 7 pro 64bit.
Load data to default bucket.
Run mbdbmaint.exe to backup data
Got error message "The filename, directory name, or volume label syntax is incorrect."
Command mbdbmaint.exe works as expected except strange error message as above.
http://screencast.com/t/5MEI8Qn0