Solution Found, maybe somebody need it too:
You must confirm that the web server are in the same domain as data server, then check the security on the directory that need to be accessed must be for internet guest account, restart the IIS.
Only that.

>>Hi all, i have this scenario: data server with a directory having dbc and dbfs inside, desktop app that access those files trough a mapped drive.
>>Web server that can access the data trough mapped drive and works fine the desktop app with logged user.
>>Now i need to access the same mapped drive using odbc and internet user (guest), but this user cant access the mapped drive even if i change the datasource to \\dataserver\inventorydata\datainv.dbc it can't get access. Internet user is with full access to that >>directory in data server but can't access. Any Ideas??

>>T.I.A.