Ah ok - I inserted the right language tag into the filename of the subtitles (.eng) and Filebot was able to rename accordingly. Thanks!

System Info: Windows 10, Filebot v 4.6, Java 8 Update 51

Groovy Pad runScript 'fn:sysinfo' output

FileBot 4.6 (r3052)
JNA Native: 4.0.0
MediaInfo: MediaInfoLib - v0.7.69
7-Zip-JBinding: OK
chromaprint-tools: fpcalc version 1.1.0 (C:\Program Files\FileBot\fpcalc.exe)
Extended Attributes: OK
Groovy ...