"invalid configuration argument " error for the call of CUDA kernel?

This type of error message frequently refers to the launch configuration parameters (grid/threadblock dimensions in this case, could also be shared memory, etc. in other cases). When you see a message like this it's a good idea just to print out your actual config parameters before launching the kernel, to see if you've made any mistakes.

You said BLOCKDIM = 512. You have threadNum = BLOCKDIM/8 so threadNum = 64. Your threadblock configuration is:

dim3 dimBlock(threadNum,threadNum);

So you are asking to launch blocks of 64 x 64 threads, that is 4096 threads per block. That won't work on any generation of CUDA devices. All current CUDA devices are limited to a maximum of 1024 threads per block, which is the product of the 3 block dimensions.

Maximum dimensions are listed in table 14 of the CUDA programming guide, and also available via the deviceQuery CUDA sample code.

Just to add to the previous answers, you can find the max threads allowed in your code also, so it can run in other devices without hard-coding the number of threads you will use:

struct cudaDeviceProp properties;
cudaGetDeviceProperties(&properties, device);
cout<<"using "<<properties.multiProcessorCount<<" multiprocessors"<<endl;
cout<<"max threads per processor: "<<properties.maxThreadsPerMultiProcessor<<endl;