Receiving an EACCESS Permission denied error when copying files to ExtSDCard
It's a Galaxy Tab, which just received an update OTA to 4.4.2 a couple weeks ago.


There you have the reason: Kitkat introduced restrictions concerning access to the SD-Card. While apps still can read from the card, only system apps are permitted to write to it (with the exception of app-specific directories in /sdcard/Android/data).

For non-rooted devices, there's no solution or work-around available (except waiting for the Lollipop update to lift these restrictions a little). There are, however, several solutions for rooted devices, some of them can be found in this list. If you're interested in those (maybe you've meanwhile rooted your device, or rooting became an option for you), watch out for apps like Kitkat external SD card patch or SDFix.