[Gvsig_english] problem or question regarding join function

[Wolfgang Qual]

Hi list,
I have a point shapefile that contains quite some addresses and corresponding 
coordinates and a big file (dbf) that contains some points of interest and 
their addresses.
As the second file contains several elements that have the same address, I 
would like to join the address layer attribute table to that table (in order 
to add the coordinate-information to the poi-layer and create a x/y-theme out 
of it). 
The join seems to work, but gvSIG will not allow me to create a x/y-theme (it 
calculates something but does not display the layer or: the layer is marked 
in the legend with a little cross, marking it as corrupt/broken).
Isn't it possible to use a table with joined-to information as a source for an 
x/y-theme? Did anyone have the same problem already? And: how to solve this 
issue?
Any comments are apprecitated very much.
Best,
Wolfgang