I have encountered this problem many, many times. It has been found that our
problem arises from the number of viewports used in a drawing. The maximum
number we can safely work with is 6. Beyond that and we will generally
always get an Error Code 10. We have tested ACAD 2004 and found that there
are no such limitations.
The problem may be linked to the size of model being viewed through the
viewports and this may change the number of viewports you can use.
This may not be the cause of your problems but we found that in 100% of
cases at our office, if the number of viewports were reduced to 6 and below,
then the errors went away.