error, it’s because your current computer has a newer version of Office (like Office 365 or Office 2021). Stack Overflow

To fix this issue without trying to locate unauthorized standalone Dynamic Link Libraries (DLLs) or Object Libraries (OLBs) online, you must configure your application to target modern Office versions or apply specific developer bindings. Understanding the Excel 9.0 Object Library

No. There is no "Excel 9.0 Runtime." Excel is not redistributable. The object library is just an interface; it cannot run Excel without the actual Excel application.

The Object Library is essentially a blueprint. It allows other programs (like a Visual Basic 6 application or an Access database) to "talk" to Excel. It tells the external program what objects exist in Excel (like Workbooks , Worksheets , and Ranges ), what methods are available (like .Copy or .Paste ), and what properties they hold (like .Value or .Formula ).

Understanding the Microsoft Excel 9.0 Object Library If you are maintaining legacy code or working on automation projects that involve Microsoft Excel 2000, you’ve likely encountered the Microsoft Excel 9.0 Object Library