PCI express could not open device, PCIE_open failed

I am using Intel DE2i-150 board where I have Intel atom processor with yocto os and fpga with Nios II processor. I am trying to access the fpga board from yocto. Initially I was able to communicate but due to some other installation now the PCIE_open is not working and it is giving me an error: "Counld not open device". This phrase is not anywhere defined in my code. I have used the driver code also but ended up with the same error. Previously it was working. I have no idea what is going on. I have installed jason-c, bdwgc, autogen, expat, gmp,guile, libffi, libiconv, libtool, libunistring, xml parser libsnd file, lib_atomic_ops,pulse_audio tried packages in yocto. Please help me regarding this.