Actually, Dean, 18.0s (LMS TECH) *is* ACA2010.
As to the OP, we need more info.
Does it happen with *all* old drawings?
For the ones that give the error, do the same files give the error every
time?
Does this happen on one workstation, or all workstations (or some)?
Does AutoCAD crash?
Does the file fail to open, or does it open anyway, just giving you an
error you can dismiss?
Possible solutions:
Try Recover on the old files.
Open with a previous version, audit & purge.
Dean Saadallah wrote:
> You also seem to have posted a partial error message :))
>
> Who or what is LMS TECH? That's not an AutoCAD error message.
> Contact them or your network administrator for help with the error message
> while you wait here.
>