Chris
I have just encountered the same problem with MindManager 7 Pro version 7.1.394. It was working before. Web exporting from MindManager is is my key tool for publishing content on the web.
Running Control Panel > Programs > MindManager > Repair did not fix it.
I was surprised by the comment Web Exports are not part of the standard. They have been in every version of MindManager I have used for the last 10 years. The process changed in MindManager X5 and the export templates in one version do not work in later versions :( but its installed with MindManager every time.
If I find a solution I will post it.
Andrew Wilcox www.cabre.co.uk
Mindjet Certified Trainer - Tablet PC user
Daily MindManager User for 10 years