I notice you're asking for an "Autotune VST" for Adobe Audition 1.5 — that's a very old version (released around 2004).
Conclusion
Why Use Autotune VST with Adobe Audition 1.5? Autotune Vst For Adobe Audition 1.5
Refresh Effects: In Audition, go to the Effects tab, right-click, and select Refresh Effects List. Your VST should appear under the "VST" category. Recommended Legacy Plugins I notice you're asking for an "Autotune VST"
Open Audio Plug-in Manager: Go to the Effects menu and select Add/Remove VST directories. Pitch Correction : Autotune VST can correct pitch
Adobe Audition 1.5, released in 2004, is a legacy 32-bit application. While it lacks built-in modern "Auto-Tune," it supports third-party VST plugins DirectX effects Recommended Autotune Plugins Since Audition 1.5 is a 32-bit program, you must use 32-bit VST versions