Internal Error: Sub-system: VPR20K, File: vpr_common/placer_lab_netlist_routines.c, Line: 1110

This internal error may occur in the Quartus^® II software version 4.1 SP2 when you compile your design targetting ACEX^® 1K or FLEX 10K^® devices.

You may be able to avoid the error with the following workaround:

1. In the Analysis & Synthesis Settings page of the Settings dialog box (Assignments menu), select Speed as the Optimization Technique.
2. In the Fitter Settings page of the Settings dialog box (Assignments menu), click More Settings.
3. In the More Fitter Settings dialog box, ensure that Auto Packed Registers is set to Off.