The problem is that you’re running your PTX file through the PTX assembler ptxas.
Make sure your nvcc command line is generating PTX code only by using the --ptx parameter.
The actual ptxas error comes from a macro which OptiX will convert to PTX code when stitching the final kernel from your intermediate PTX input. Only the final kernel will be sent to the PTX assembler during runtime of your application later on.