Can't join surfaces
From:
Frenchy Pilou (PILOU)
22 Jun 2011 (4 of 22)
4345.4
Kill the magenta surface
Join the four curves of base of the orange
Select the 4 blue curves
Make network
Kill all curves and edges
Join Dome
Boolean Union all orange element
seems you had some surfaces overlapsed
EDITED: 22 Jun 2011 by PILOU