Symptoms

During FlexiCapture 12 installation the following error is thrown:

Internal program error
D:\Build\TeamAgent\_work\5\s\Awf\Src\ToolBarAwl.cpp, 158.

Cause

This is a known bug that was fixed in FlexiCapture 12 Release 4 Update 3 Patch 1

Resolution

As a workaround, it is possible to switch the FlexiCapture 12 language to English:
How to change the FlexiCapture interface language