After some brief digging, it seems like you're trying to use the stlread on the file exhchange rather than Matlab's stlread which isn't meant to be an input to patch.
If you want to use the 3rd party function, download it and make sure it's on the Matlab path using addpath.
Otherwise, it looks like Matalb's stlread output is supported by trisurf() which may or may not be suitable for what you're trying to do.
