State Sourced Income

Greetings all.

I'm working on a State return (for the State of Pennsylvania) for a Trust. The only income I have to report is for interest, dividends, and capital gains, and I'm trying to determine what is considered “Pennsylvania Sourced Income”. None of the financial institutions are located in Pennsylvania, but the Trust is. TT is treating a portion of that income as State taxable, and I try as I might, I can't figure out where TT is getting it's numbers from.

Any assistance would be most appreciated.

Thanks

PS: TT is entering numbers that it has calculated (apparently from one or more other forms), but then it is flagging one of those numbers (that it calculated) as an error, and stating that it is too large.