Espuelas,
Yes, it's possible to do this. It just takes a little hunting.
1. Open the report in a Design window.
2. Select the chart and then inspect (right-click) it.
3. Choose Object Explorer from the shortcut menu.
4. When the Object Explorer appears, make sure that the Tabbed pane is visible (by choosing either View | Both or View | Tabbed Pane).
5. Select the Appearance tab and then look for the property called Label.NumberFormat.
6. Set it to W.4 or whatever you need it to be.
7. Save and run your report.
Mind you, this assumes you're using Paradox 9. The specific menu commands may be different in different versions of Paradox. but the basic idea is that you're looking for the Label.NumberFormat property and you want to set it to a value compatible with the standard numeric formats used by Paradox.
Hope this helps...
-- Lance