I ran into the same prob few mths ago. Seems that 7.0 Free version updates from different server than Pro version. Since most users run free version, related server seems overloaded. Try following countermeasure:
Edit the 'hosts'-file on individual PC's and add the 'guru' line below the 'localhost'-line as follows
127.0.0.1 localhost
193.86.103.19 guru.grisoft.com
Win98:
C:\WINDOWS\hosts (Open with notepad & append 193.86.103.19 guru.grisoft.com below line '127.0.0.1 localhost')
WinXP:
C:\WINDOWS\system32\drivers\etc\hosts (Open with notepad & append 193.86.103.19 guru.grisoft.com below '127.0.0.1 localhost')
Regardless the free version initially tries to update from the free-server, it will now point to the Pro updateServer.
Both free as pro 7.0 versions do use same updt definitions.
See this countermeasure as a temporary one until situation stabilized.