http://www.theforce.net/swtc/preq/tpmcont.html
"Considering the wealth of Naboo, and its relative proximity to the sector containing Tatooine, what stopped Queen Amidala from dispatching her agents to purchase the freedom of Anakin's mother? What does this tell us about the political and economic situations on Naboo and Tatooine? Was Shmi sought, but impossible to find? Did Watto's trouble with Gardulla the Hutt after the podrace [Qui-Gon Jinn one-shot comic] affect Shmi's fate and isolation from Anakin's allies?"
Never thought about that, but that is strange. Lol, do we try to fix this problem too?