Handle edge cases in import

**Problem**
When working with config, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

No file, test, or entry point is named. Start by locating the config import path and its existing error handling, then identify the import edge cases covered by current behavior. Done means the relevant failures produce more descriptive errors and tests or reproducible checks cover the changed cases.

Written by the indexing model from the issue text.