You're seeing an error because your .NET 3.5 SP1 offline installer isn't finding necessary Windows components. Despite the name, .NET Framework 3.5 SP1 does include the base 3.5 framework, and applications
Official Site typically require the latest service pack. For an offline Windows 10 machine, the most reliable fix is to use the DISM tool with your Windows installation media (ISO/USB). Mount the ISO (e.g., to X:), open Command Prompt as Administrator, and run Dism /online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:X:\sources\sxs. This will install .NET 3.5 (including SP1) using local source files.