Description
This error will occur when you try to generate a system
using SOPC Builder 3.0 if the sopc_quartus_dir variable is
not set in the .sopc_builder file included in your Quartus
install.
The .sopc_builder file is located in the <Quartus root>\sopc_builder directory. To rectify this problem ensure that the .sopc_builder file contains a variable called sopc_quartus_dir which points to your Quartus install directory. For example:
sopc_quartus_dir = "C:\QuartusII_3.0_SP1";