I just downloaded the latest version from the original website and there was no problem.
http://notepad-plus-plus.org/download/v6.5.1.html

Virustotal shows no suspicious things:
https://www.virustotal.com/nl/file/d42fe7e3fd4ee26cae5aa249e5ae4ece921f736f4c6b2a2d0f203da0d7f9e155/analysis/

There are however security risks for tuxfamily.org:
http://zulu.zscaler.com/submission/show/de96f482b10a56d8006d52c590cbab1c-1385054982
http://urlquery.net/report.php?id=7854565