It appears that FreeBSD renamed iconv_open() to libiconv_open() and it's causing the Java Service Wrapper binary to fail. For now, I've moved the wrapper binaries and libraries from bin/ and am using the version I can install through pkg. I think you might need to pull in an updated version... it looks like version 3.5.23 or better from the ticket: https://sourceforge.net/p/wrapper/bugs/283/.

What I find especially odd is that this had been working until recently after updating some things in FreeBSD. I guess what I had was pretty out-of-date (we don't tend to keep it very up-to-date, since some of the tooling is rather... primitive).