advanced rendering for AutoCAD
Unfortunately, I can't be of much help here for you - but as far as I'm aware of - nXtRender does not use any type of proxy or object enablers (and if it does, you should not be getting the error as it would know how to read those anyways). I'm guessing this is more of an AutoCAD issue than it is a nXtRender issue, but then again, I don't know why it's explicitly saying ACCURENDER? Hopefully someone else can help shed some light on this for you.
the hidi error happens went I use accurender on autocad for rendering and the proxy situation it happens went I open an autocad drawing that contaings some blocks and the error window said that acurrender application is mising.. dont understand, I been using autocad since 2000 and accurender since four years and this is a weird thing, never happens before.... wonder..!! I erase autocad and acurrender and Installed again but still the same thing... im using autocad 2010 and acurrender build 349.
After some searching, it appears that nXtRender can (or does?) use proxy information. I have never seen a warning - but I believe I have my warnings shut off (we deal with allot of outside drawings). Here is a post on the forums dealing with that - and as Mike says at the end of it, just shut the warnings off, it will not hurt anything.
As for the Heidi driver error, I did find this from AutoDesk: