The two connecting pieces are 0.8mm wide. Is anywhere near the extrusion width for your Rostock? If so, the connecting pieces may be too narrow for S3D to slice.
If so, the solution is to reduce the extrusion width to less than 0.8mm, if you can that is!
Before we go too far on this.......I've noticed that if you have a negative z offset where the height of the brim/skirt is less than the z offset, then the brim/skirt will not be visible in the preview if you're looking from above......the virtual build plate gets in the way! Rock the view so you're...
PLA is one of those materials that appears to be somewhat difficult to dissolve...see this blog for some easy-to-understand experiments in dissolving: http://www.vinland.com/blog/?p=68 And finding a solvent may be a little dangerous!! Try Googling the subject!! Personally, I use Loctite superglue to...
Can this be changed so that it first sets all temperatures and only then waits for them all to be reached? It is a pain waiting for heating to be completed in a one by one manner. It's all in the order of the commands in the start up script. Read this thread and look at the scripts in both threads....
At a guess from the very brief description of the issue, I think this may be cured by using the "Separate Connected Surfaces" option on the Mesh dropdown menu. Using this option may add one or more items to the model list. If it does, then the problem may be solved. If not, attach a factor...