Halloween Approximately - S2-E2
Continuity mistake: When Francis walks into the boy's room the calendar says September 2000. In the next shot it changes to October 2000. After that Reece says "No, it really is the 31st" he flips up the September page of the calendar to October. (00:06:15 - 00:07:15)
Continuity mistake: In the bowling alley, the design above the pins is blue and pink pins. While in the back of the bowling alley, above the pins is a different design.
Continuity mistake: In the side of the story when Lois takes the boys, Malcolm has some kiddy bumpers put in to help him bowl. In the next scene when Reese is about to tell Beth the joke, you can see the lane which Malcolm was just at but there are no bumpers in the gutters. Then later when Malcolm stands up to Lois they are back in the gutters.
Answer: It is made up - although it is implied she is Croatian, she never mentions it herself.