This error indicates that a third-party DirectX plugin is not loading properly.
The easiest fix is turning off the loading of DirectX effects:
In Mixcraft, click on the File menu and select Preferences. In the Miscellaneous preferences, turn off the "Load DirectX Effects" option.
If you want to just stop the one troublesome effect from loading:
Examine the contents of the mixcraft-log.txt file from the Acoustica Mixcraft folder and see what the last effect that loaded was named.
Note: starting with Mixcraft 4.5, the log file is located in the %appdata%\Acoustica\Mixcraft\ folder.
For VST effects, edit the VSTignore.ini file (using notepad) and add the name of the effect.
If it is a DirectX effect, edit the DXignore.ini file and add the name of the effect.
For example, if the effect is called "MyFX Reverb", you could add a line to the appropriate file that would look like this: MyFX Reverb You could also exclude a whole group of effects by just adding the first part of the name: MyFX That would exclude MyFX Reverb, MyFX Compression, MyFX EQ and so on.