Flutter and Web3dart Expert

I am looking for a developer who can fix a smart contract error in my flutter application. The error message I am receiving is currently unknown. I have tried several solutions to fix the error but none have worked so far. The smart contract involved is a custom contract, so experience with custom contracts is ideal for this project.
I am looking for a Flutter developer who can integrate Web3 capabilities (smart contract) into my project. Specifically, I need someone who can handle moderate level smart contract integration on the Binance Smart Chain. The ideal candidate should have experience with Web3, Flutter, and be familiar with the Binance Smart Chain. I have already an application built in Flutter and i need help in integration but we got an error while running a function call BalanceOf

Got an error while running the code
Error code : [Unhandled Exception: Range Error: Value not in range: 32]