DDE to Word Suddenly Broken - Windows 10

I've been using a programable database (Superbase) that does a fairly simple DDE call to Word to initiate a Mail Merge macro. 

It's worked fine for (literally) decades, but suddenly it's freezing and doesn't complete. Barely starts.  

This is the Superbase program which uses its own variation of BASIC 

DDEtoWinword: 

DDETERM 1 

DDEINIT 1,"WINWORD","SYSTEM" 

M$ = "SuperbaseMerge" 

Q$ = CHR$ (34) 

DDEEXEC 1,"[toolsmacro .name=" + Q$ + M$ + Q$ + ", .run]" 

DDETERM 1 

END 

The Q$ and M$ variables are just to concatenate the longer macro name. 

It seems to freeze right away after the 2nd line DDEINIT 1,"WINWORD","SYSTEM". 

Has Word changed it's DDE name? 

Is the “SYSTEM” topic no longer valid? 

I’ve tried manually forcing the opening and closing of the DDE channel (through Superbase) to no avail. 

Superbase freezes and is unresponsive. I have to kill it in Task Manager NTVDM.EXE 

Superbase is a 32 bit app running in 32 bit Windows 10 Pro. Word is from Office 365 Apps for Business. 

Used to be if it hung like this, clearing the TEMP directory and restarting Windows got it working again. Not anymore. 

Anything else I can try? 

TIA for any guidance. 

Cheers!