We have looked into this problem and found its cause: this misbehavior is caused by FLStudio's 64-to-32 bit bridge (we checked it in FLStudio 10.0.9), when one tries to load 64-bit version of a Voxengo plug-in. To avoid this issue, please use 32-bit versions of Voxengo plug-ins in FLStudio.
This is a known issue which may happen if the plugin is internally loaded via built-in bit-bridge of FL Studio. To overcome the issue make sure to install the same bit version of plugin as FL Studio has itself.