The error types in this file that have not yet been converted are documented here:
Invalid spec length + 25 Type 0 (Unknown) Layer 12
This message means that a CAD or CLD file was found that we cannot process. The reason as we saw it is given in the message. Please try to open the file with your CAD or Composer system. If it seems to be fine, send it to us for analysis. If not, there may be a problem to be addressed at your end.