This value must be between 1 and 999. The closest allowable value

no its not working

There's really no direct way to open an 8.1 file in 6.5. Quark doesn't make it easy to do these things. The only thing you can do is save 8 down to 7 down to 6, but there's a lot of new stuff between the versions, so if you had the access to do that, you'd most likely lose formatting and information.

I am not sure why they should not be able to open them as they should be able to be opened on 7 the only thing I would suggest is to make sure that the suffix of the filename ends in qxp e.g. filename.qxp however if the company is going to amend them in 7.1 and they are using a 7.1 xtension you may not be able to open them or the file may not render properly.

However if it is for proofing purposes you could send them an acrobat pdf file

Hope this helps.

Please Navigate to HDD>>Users>>Home User>>Library>>Preferences>>Quark>>QuarkXPress 6.0 folder and delete all the files present in that folder.

Also check if there is any Preferences folder under HDD>>Applications>>QuarkXPress 6.0 folder, if yes then delete that folder as well.

Now launch QuarkXPress and try opening the documents and check if it helps

Please Navigate to HDD>>Users>>Home User>>Library>>Preferences>>Quark>>QuarkXPress 6.1 folder and delete all the files present in that folder.

Also check if there is any Preferences folder under HDD>>Applications>>QuarkXPress 6.1 folder, if yes then delete that folder as well.

Now launch QuarkXPress and check the results.

Thats not possible.
QuarkXPress 7 would allow you to downsave to a QuarkXPress 6 document but not to QuarkXPress 4.

you would have to open the document in QuarkXPress 6 then save to version 5, then open the same in QuarkXPress 5 and then downsave to 4

As time goes on software applications tend to change enough that an older version produced file is not forward compatible with a new version. For instance some of my MS Office files no longer can be opened by the latestr version of "Word", hence Microsoft issued a plug in that will allow you older "Doc " files to be read by the latest version of "Word", same thing holds tru for FLASH program, every time a new version of FLASH comes out, the older version can not be read by it.
You need a version of QuarkXpress that can read this doc, If you created the original document, the you can go to your version of QuarkXpress to open the document or if possible ask the originator of the document what version they used to create the document.

Please Navigate to HDD>>Users>>Home User>>Library>>Preferences>>Quark>>QuarkXPress 6.x folder and delete all the files present in that folder.

Also check if there is any Preferences folder under HDD>>Applications>>QuarkXPress 6.0 folder, if yes then delete that folder as well.

Now launch QuarkXPress and check the results.

Just downsave the project by going to File>>Export layout as project and choose the version as QuarkXPress 5.
once done open in QuarkXPress 6 and save it

Please let me know when exactly does QuarkXPress crashes