I can't download this version:
The document name you requested (/down/gstudio_770.exe) could not be found on this server. However, we found documents with names similar to the one you requested.
Available documents:
/down/gstudio_750.exe (mistyped character)
/down/gstudio_760.exe (mistyped character)
The version 7.66 also seems to be gone.
EDIT: ok, its on the download page now as an official version.