Not sure what I'm doing wrong, but when I try to import a collection, (30+), of closed polylines to act as sub basins in SSA, they come in fine. However, if I try to save, or close and reopen the project file, I get an error message, saying the file is damaged.
From C3D, I exported the polylines as shp files, then imported them into SSA. I can import the pipe networks fine, it seems to be the basin objects, (polylines), that are causing the problem. Can't find where anyone else has posted this problem. Also, I just installed SP1 for C3D 2012 a few days ago. I would have thought that the SP would have included any known hotfixes.
I would either suggest opening a Subscription supprot request - or post the SHP file here together with whatever information you have specific to the issue.
I managed to make it work by changing what at data attributes I selected when creating the shp file. I found that if I selected Object Properties, instead of just Properties, then SSA accepted them.