questions about buffer size and parameter size.

Is it the "clCreateBuffer" call that is failing or the "clEnqueueWriteBuffer"? Please post the exact OpenCL error code number. Furthermore, is this the only buffer you are allocating on the device or do you also have other buffers?

If you just need to pass offset values, you can just put all the offsets in an array and pass a pointer to that array, instead of passing a pointer for each offset. Then use the offset value in the kernel to adjust your starting point for reading data from external memory and feeding it into your HDL library.