I'm guessing there is a problem with the symbol. I will need to see your Sunstone PCB123 Files
that shows the issue along with the schematic library file that contains the symbol. Is this only happening with one part or multiple parts? Would you please email your file to email@example.com
for review? If the issue exists with only one or a few custom symbols please also send the .sym file that contains the problem symbols. You can find your custom symbol libraries by using the PCB123 files shortcut found in your My Documents folder then navigate to the Lib Custom folder. Your customer .sym libraries are located in the Custom folder.
The direct path to the Lib\Custom folder will be one of the following.
XP: C:\Documents and Settings\All Users\Application Data\PCB123\Lib\Custom
Vista and Win 7: C:\ProgramData\PCB123\Lib\Custom