have error in DSP builder when I use signal compiler

Make sure that you don't have any residual DSP Builder blocks residing in the _import directory (or any of the other directories w/in the project). I had an issue like this in which there were multiple versions of certain FIR filters (but I was only instantiating one of them in the actual MDL file). When the <module_name>_add.tcl file is run in Quartus, it basically looks for any .tcl files in any of the directories and tries to run them. In this case, I traced through the errors in the processing window, and it was trying to load blocks that weren't necessarily valid, just because there were files leftover.