One of the new frequencies introduced in EViews 7 is Daily-custom week. One permutation of a daily custom week is a weekly 1 day week. Consider a weekly 7 day week but instead of 7 days constituting a week, only 1 day constitutes a week. EViews does not consider this frequency as weekly and therefore cannot be stored in older databases.
Can you verify your workfile structure/frequency (double click 'range')? In the frequency box, displayed should be either 'weekly' or 'daily -custom week'. If neither is listed, you have something other than a weekly frequency and it also may not be supported by older databases.
If 'weekly' listed then please verify EViews is up to date (Help->EViews Update) and then try again.
If 'Daily- custom week' is listed you will need create a new EViews database, copy all of the objects from the old database to the newly created one and then just work from the new one. If your workfile is structured in this manner, how did you create your workfile? Did you manually specify a custom week or did you import some data and EViews determined the structure for you?
A manually specified frequency is fine but EViews should not automatically determine 'Daily -custom week' as the frequency. If this occurred and if possible, please send a copy of your data to
support@eviews.com.