Adding patch banks to Dexed

I just got a new DX7 patch bank and want to add it to Dexed in Zynthian. I’ve tested it and it works on Dexed on my computer as well as miniDEXED. But when I try to upload it to Zynthian via the “presets and soundfonts” webadmin screen, I get this:

Can't install file: Conversion from syx to LV2 failed! => Command 'cd /tmp; /usr/local/bin/preset2lv2 dx7syx "/zynthian/zynthian-webconf/tmp/DehliMusikk_DXtraterrestrial_1.syx"' returned non-zero exit status 127.

So I tried going in via sftp and dropping the .syx file into the /zynthian/zynthian-my-data/presets/sysex folder. The file copies OK, but I don’t see it in Zynthian even after a reboot.I thought I had added .syx files to Zynthian before, but maybe I’m thinking of something else. Obviously I’m doing something wrong…