Hi,
to get it to work you should first remove the old directory with
rm -rf /usr/share/icingaweb2/modules/incubator
and then just copy the following block and paste it to your command line. Then it should work 
MODULE_NAME=incubator
MODULE_VERSION=v0.5.0
MODULES_PATH="/usr/share/icingaweb2/modules"
MODULE_PATH="${MODULES_PATH}/${MODULE_NAME}"
RELEASES="https://github.com/Icinga/icingaweb2-module-${MODULE_NAME}/archive"
mkdir "$MODULE_PATH" \
&& wget -q $RELEASES/${MODULE_VERSION}.tar.gz -O - \
| tar xfz - -C "$MODULE_PATH" --strip-components 1
icingacli module enable "${MODULE_NAME}"