NetSurf's Run file includes the line RMEnsure AcornURI 0.12 Error NetSurf requires AcornURI 0.12 or later. A version of this can be found at http://sudden.recoil.org/others/
That link 'could not be retrieved', and I've not been able to locate the current download url for AcornURI. However, in fact, the link is not needed, because AcornURI 1.04 is included in the distribution zipfile. Maybe the error message in NetSurf's Run file should be changed? Tony