R's install-info invocations are not failsafe against read-only-netsharedpath-/usr/share installations; appending "|| :" to the invocations in %post and %preun would fix it. Checking for existence of the info file helps only with excludedocs installs, not when install-info tries to write to /usr/share/info/dir. More info: http://fedoraproject.org/wiki/Packaging/ScriptletSnippets
Resolved in 2.4.1-1, thanks for the report.