Thanks for writing back and clarifying the matter. Unfortunately I can't help you, as we are not supporting or developing de4dot. In fact, our plugin still uses de4dot version 1.9.1 and from your screenshot I see you try out version 2.0.3. I suggest you get in touch with the folks creating de4dot via the email or the site they have provided in the error report. I'm sure they'll have the knowledge needed to answer your questions.
Regarding the existence of another deobfuscator - we do not have another deobfuscating plug-in. There are probably another deobfuscating tools out there, but as far as I know, de4dot fits our needs best.
the Telerik team