npm install bcrypt on ubuntu 12.04.5LTS

I tried to install an node app. But when I start the npm install i get the following errors:

Execution filemng has failed with exit code 1, stdout:
> bcrypt@0.8.7 install /var/www/vhosts/kobelka.de/opencloud.kobelka.de/openhab-cloud/node_modules/bcrypt
> node-gyp rebuild
make: Entering directory ...
make: *** [Release/obj.target/bcrypt_lib/src/bcrypt_node.o] Error 1
gyp ERR! build error
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack at ChildProcess.onExit (/opt/plesk/node/7/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:276:23)
gyp ERR! stack at emitTwo (events.js:106:13)
gyp ERR! stack at ChildProcess.emit (events.js:192:7)
gyp ERR! stack at Process.ChildProcess._handle.onexit (internal/child_process.js:215:12)
gyp ERR! System Linux 2.6.32-042stab120.5
gyp ERR! command "/usr/local/bin/node" "/opt/plesk/node/7/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /var/www/vhosts/kobelka.de/opencloud.kobelka.de/openhab-cloud/node_modules/bcrypt
gyp ERR! node -v v7.6.0
gyp ERR! node-gyp -v v3.4.0
gyp ERR! not ok
npm ERR! Linux 2.6.32-042stab120.5
npm ERR! argv "/opt/plesk/node/7/bin/node" "/opt/plesk/node/7/bin/npm" "install"
npm ERR! node v7.4.0
npm ERR! npm v4.0.5
npm ERR! code ELIFECYCLE
npm ERR! bcrypt@0.8.7 install: `node-gyp rebuild`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the bcrypt@0.8.7 install script 'node-gyp rebuild'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the bcrypt package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node-gyp rebuild
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs bcrypt
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls bcrypt
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR! /var/www/vhosts/kobelka.de/opencloud.kobelka.de/openhab-cloud/npm-debug.log

The solutions I found didn´t work for me:

-build-essentials and python2.7 is already installed

via Jörg Pelka