I don't know what exactly your problem is, I guess you have an imported geometry that consists of several surfaces that aren't stitched. Usually, there are two work arounds for that:
1. Use the "Stitch Suface" command (Master Modeler, row 4, column 3, in the pop-ups).
2. In I-DEAS 10, theres a tool called "Match Edges" (Master Modeler, row 5, column2, in the pop-ups) that you can use to "mend" gaps between surfaces by aligning the gapping edges.
If neither 1. nor 2. help, the only way I could think of would be to manually create missing or misaligned surfaces (e.g. by the "Surface by Boundary"-command).
Hope that helps,
Daniel