conversion problems from one format to another

Hey Sarah,
You can try two things before thinking about re-digitizing.
1. Switch the Software for the conversion. You can use the free wilcom "truesizer" or "my editor" from wingsxp. I had ones a problem converting a file in tajima pulse but with truesizer it worked.
2. Try to save it as DST or emb before converting it to .pes maybe this will solve your problem.

Indeed, it depends upon how each program determines the stitch data.
It is the equivalent of pictures where some formats are raster bitmaps, while others are vectors.

So for embroidery some files store the data for every stitch and machine code, whereas others store for blocks and densities, so effectively calculate the stitches every time.
This makes sense in terms of file size and flexibility when it comes to resizing.

However, if one format uses individual stitch data and you need to convert to one that uses blocks, then it is down to how the conversion creates those blocks from individual stitches. As you have discovered, some programs can throw up problems and the only way is to try different methods, edit the incorrectly translated areas, or re-punch the design.