Does anyone have experience with balancer v2 vaults?

I am trying to add liqudiity to a vault , but it keeps reverting with an invalid opcode error


bytes32 poolIDOmniUSDCavax = IBasePool(OmniUSDCavax).getPoolId();
IVault.JoinPoolRequest memory request;
request.assets[0] = IAsset(OmniUSD); // It reverts here
request.assets[1] = IAsset(USDCavax);
request.userData = abi.encode([100, 100]);
request.fromInternalBalance = false;