Problem
You are getting this error message when starting Adobe Acrobat X
acrobat failed to connect to a DDE server
Soultion
Modify this registry Key:
HKEY_CLASSES_ROOT\acrobat\shell\open\ddeexec\application
Change value “AcroViewA10” to “AcroViewR10”
I just checked my root entry and it is already showing r10 nd it will not open the pdf and comes up with failed to connect to a dde server