with yoruself an IL resident, all the income on the 1099-R is potentially taxable by IL (Coming from a firm based in TX is immaterial).
So, an "IL" in the first half of box 15 would be appropriate. An IL registration number in the second half of box 15 shouldn't be required, as long as no taxes were withheld in box 14 (leave box 14 blank...don't put a zero in there)
__________________
If the software complains anyhow, then as a second attempt, you could try leaving boxes 14, 15, 16 entirely blank.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
