We saw that error on older versions of Sage 300 when 64-bit Excel had been installed (instead of 32-bit).

Thanks Jim - we are on an older version but have 32bit Excel running

Orchid Systems is in North Sydney.  They are a premier independent developer for Sage 300.  If they cannot help you, they will likely know someone in the area who can.  About Us | Orchid Systems  Contact info at bottom of that web page.

Thanks Jim - You are gentleman and a scholar!

Hi Michael, this issue has occurred for our clients in several ways:

1. Antivirus behaviour detection kills the RunDLL process that launches the Statement Designer.  Locate the error in the Event Viewer on the affected machine or check your Antivirus/AntiMalware logs for events and detections.  In particular I've had HitManPro (part of a Sophos suite) kill it at a couple of sites producing this error.  Whitelist your Sage 300 Programs folder to exclude it from scanning over the network in the central management area of your AntiVirus/AntiMalware.
2. AppLocker kills the process - put an exclusion in AppLocker though this should show in the Event Viewer.
3. Add your Sage 300 programs share to the Trusted Locations if you're blocking Macros from running outside the Share.
4. How old is old for your Sage 300 version?  There is a limit to how far back you can go with the latest (even 32-bit) version of Excel 365 but I can't recall specifics.

Definitely build that relationship with Anne, Sheena and the crew at Orchid Systems - they're exceptional!

Thank you

Hi Michael,
Had this at a client a couple of weeks ago, run regacc.exe \\....\runtime\regacc.exe with right click run as administrator and run with domain admin and that reset the registry and it worked.