I have installed pd-extended from the pd homepage, i am running pd-extended 0.43.4 on macOS Sierra 10.12.3 64-bit and now i get the following error in the console by starting pd-extended:

WARNING: 64-bit builds are still beta, some libraries are known to have serious issues (cyclone, maxlib, moonlib, moocow, pdp, bsaylor, etc.)
For more info, see the README.txt in '64-bit-warning-plugin' in the Help Browser

and the pd crashes immediately, i can fix it?

@vSeiya NOTE: It may be possible to run individual applications in 32-bit mode (Get Info on the application in the Finder and tick "Open in 32-bit mode" - if that option is not there you can't).
From this page........ http://www.macstrategy.com/article.php?163
So maybe not? if you cannot install the 32bit version of extended.
David.