Improve error messages in parsers

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

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

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

The issue names parsers and store-related errors but no files or tests. Start by locating the parser entry points and existing error-handling tests, then reproduce representative store failures. Done means the affected errors provide more descriptive debugging context and the behavior is covered by tests.

Written by the indexing model from the issue text.