I am trying to split my database an error appears "|9 was unable to export the data.".

[sonic8]

Can you guide how to remove this error?

I have no idea what causes this error.
As splitting a database is usually a one-off operation, I would follow the line of suggestions by @CJ_London starting in #3.
The errors you encountered along the way, indicate there could be something wrong (corruption) with your database file.

 

[LarryE]

Please attach a copy of your database for us to analyze. It's the only way to help you. We will look at each field in each table to determine if there is a problem with your tables or the data in them. Then we can attempt to split it ourselves to see what happens. We can only speculate at this point. If you want to share your database with another user, then the split back-end file needs to be placed on a shared-drive, so make sure that is what you are attempting to do first. I assume that is what you were attempting to do, but again, just speculation.