Download the latest version of uniscribe engine (usp10.dll) from here. Installation instructions are included in the zip file.

Downloading this dll is NOT necessary for running Avro Keyboard.
When to update this dll:
MS Office Problem...
If thinks are not perfect...

Updating the dll for MS Office may be necessary in all versions of Windows- Read This Topic)

Thanks for your time.

Disclaimer: This usp10.dll is a property of Microsoft Corporation.