...
Labels can be created on-the-fly.
Error “Unable to create basket line part requirements”
...
This issue can be encountered in the following situation
You created the Catalog part using the new Create Catalog part form (from version 24.5 onwards)
You have one or several Part Requirements forms enabled
The admin panel setting Home › B3_Organization › Organizations › <YOUR ORGANZATION> - “Make Catalog parts not changeable” is enabled
Solution
Disable “Make Catalog parts not changeable”
OR Disable the Part Requirements form(s)