Error trying to register a pass

~/llvm/llvm_core/llvm-2.9$ opt -load …/llvm-2.9/Release/lib/LLVMHello.so -hello cdfg.c
Error opening ‘…/llvm-2.9/Release/lib/LLVMHello.so’: …/llvm-2.9/Release/lib/LLVMHello.so: undefined symbol: _ZN4llvm12PassRegistry12registerPassERKNS_8PassInfoEb
-load request ignored.
opt: Unknown command line argument ‘-hello’. Try: ‘opt -help’

I’m getting the above error, I’m unable to register this pass and use it. There is very little information about this error on the net, any ideas? Thanks.