When a program is coded using .NET 1.1, it cannot natively run on newer versions like .NET 4.8 or .NET 6.0 due to breaking changes made over the last two decades. It requires the original 1.1 runtime files to execute commands. Where to Download .NET Framework 1.1.4322 Safely
If the automatic installer fails, you can attempt a manual install:
Proprietary business tools that were never updated by their vendors.
( NDP1.1sp1-KB867460-X86.exe ) 2. Trusted Third-Party Archives