I've open a DBF file into excel 2007,

so the columns with date format its returns:

FEC_VEN

05/01/2011

07/01/2011

20110107

20110108

09/01/2011

I changed the regional configuration in the system, and the trouble still.

then i've open the file on another system (PC with excel 2007) and the columns with data format shows me perfectly.