can't create the <project_name>_syslib.a file while building

I've added a new component to my current project. The compilation of sopc builder and quartus II were successfull. But when I built the NIOS II application under NIOS II IDE, I got an error 2 with no details. After the observation, I've found that the <project_name>_syslib.a file was not created while building the <project_name>_syslib. If I copy the HAL srcource files under the directory of <project_name>_syslib, it works. And originally the HAL folder is under the directory of my new component folder which is under the directory of my quartus II project. The HAL folder contains two folders, src and inc. I've written the component.mk file under src. And when I build my project, it can find the <quartus_project>/<new component>/HAL/inc directory and the <quartus_project>/<new component>/HAL/src directory. But it just does'nt create the <project_name>_syslib.a file!! Why??