I'm having exactly the same issue. In my case, it's the E: drive on one particular server. Works fine across multiple drives on other servers. Nagios reports, "(Return code of 139 is out of bounds)". Ran check_nt directly, and here's the result:
[root@esglxit01 libexec]# ./check_nt -H asgw3ex01 -v USEDDISKSPACE -p 12489 -l c -w 90 -c 95
c:\ - total: 19.53 Gb - used: 11.65 Gb (60%) - free 7.88 Gb (40%) | 'c:\ Used Space'=11.65Gb;17.58;18.56;0.00;19.53
[root@esglxit01 libexec]# ./check_nt -H asgw3ex01 -v USEDDISKSPACE -p 12489 -l e -w 90 -c 95
e:\ - total: 273.45 Gb - used: 259.96 Gb (95%) - free 13.49 Gb (5%) | 'e:\ Used Space'=259.96Gb;246.11;259.78;0.00;273.45
In the above example, the C: drive reports fine, but the E: reports the out of bounds error. Both are using the same version and config file on NSClient++, and the Nagios config file for that server uses identical settings for C: and E:. I've tried shifting the 90% and 95% to 91% and 96%, I've uninstalled and reinstalled NSClient++, and still no joy.
Is there a bug submission system for Nagios? Since the result from NSClient++ is basically identical, I'm assuming that the bug is in Nagios or in the plugin.