Autodesk has a pretty cool free tool called Design review with an add on called trueview. The trueview should open a dwg and be able to convert it to dxf that V21 can read.
I have it loaded so if you want me to test it for you first before you download and install it, post a sample dwg and I'll output a dxf to see if you can load it into V21.
If it works, its pretty cool also as it allows you top annotate and markup drawing without the program, so you could even direct customers to the program to work with you on certain things.
Anyway look at those 2 programs.