pgsql2shp - Could not create dbf file

Hi everyone:

     I got an error when I use pgsal2shp.

     My server is Linux

     The command I used is: pgsql2shp -f newroads gisdb testarea

     Where, newroads is my out put file name, gisdb is database name, and testarea is table name.

     After hit enter button, I got the message:  Initializing... Could not create dbf file

     What was wrong? Any help will be appreciated.

Fay