make sure you have it all installed to the latest released versions and only one of each in one single place--check whether you may have disparate installations, one under /usr and other under /usr/local; when all sorted out, rebuild qtractor from scratch.
it looks like libLILV aka. drobilla's lightweight LV2 implementation stack, is not aligned properly:
http://drobilla.net/software/sratom/
http://drobilla.net/software/sord/
http://drobilla.net/software/serd/
make sure you have it all installed to the latest released versions and only one of each in one single place--check whether you may have disparate installations, one under /usr and other under /usr/local; when all sorted out, rebuild qtractor from scratch.
hth.
cheers