Resolved 22001, 1406, Data too long for column 'slug' at row 1

Hello,
In virtuemart products language table the slug field is defined to have about 192 characters and that is the maximum it can store when you run the import. You must be importing slug longer than 192 characters and so you see the error. Try to import small text for slugs and see if error is fixed.

how can I know which line of the file or row is it?

Hello,
This issue is not related to RO CSVI so cannot be fixed in RO CSVI files. We recommend to use shorter slug text in import file as slug is also used for your SEF URLs and you will be getting some crazy long URLs.

If you still want to fix this error, you need to edit the Type column of slug field in #__virtuemart_products_XX_XX table where XX_XX is the language string. See attached screenshot. By doing that with any VirtueMart update the table definition can be reset.

is there anyway of creating a RULE to strip the string according to character numbers?

Hello,
You cannot strip based on number of characters but you can get a part of string using RO CSVI Multi replace rule plugin and using Substring operation.