an error about infering RAM to FPGA

Can I ask a question about FPGA? My MSc project is to synthesis a MCU to DE0 FPGA and mesure the power consumption of MCU. I want to infer a RAM and ROM to FPGA which as the data memory and program memory. But when I synthese this two module and my openMSP430 core to FPGA, it compile fails. The top level contains the openMSP430 core, the ram and the rom. It show an error that contains too much type register nodes which is exceed the device contains. Before this I have tried a simple example, which is only read or write data to the RAM which has been initialized with "$readmemh" function. It works and show contains 0 logic elements. I have checked the infering RAM and ROM in the quartus handbook, but I didn't fina the reason. Thank you very much.