[Kishorechand]

Hi folks,am currently trying to model a 3-D heat and fluid flow problem in a porous evaporator of a capillary Pumped Loop(C.P.L),in fluent 4 solver.I am a beginner and i created a 3-d volume of 3 zones,solid,porous and fluid in gambit and meshed each volume individually using the following way:
1)Meshed 3 edges of each volume for meshing the volume individually ,
2)Meshed the whole volume individually using ,Volume command button--->Volume mesh
I ensured the regularity of each nodes at various zone interfaces by properly setting the node intervals while meshing the edges for each volume.And then after trying to export the file as "xxxxxxxxxx.GRD",am finding an error which says,"Error:Sets of disjoint elements found.All elements must be connected".

What does the error means,and what is the problem??Please suggest me a solution...