Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Continuity mistake: Arnold Betrays Iggy: When Arnold goes to Iggy's home near the start, the front doorknob is on the left side of the door, but the next time Arnold goes to see Iggy to bring him the box of chocolates, the front door opens the opposite way, with its doorknob now on the right side of the door. (00:01:20 - 00:06:40)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Continuity mistake: Helga and the Nanny: Near the start, in the shot where Miriam leaves to go to work, there is an orange vase with flowers on the table, which was not there in the previous shots. (00:11:53 - 00:13:09)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Other mistake: Helga and the Nanny: Near the start, in the shot where Bob leaves the kitchen to answer the door, watch as Helga's mouth opens and closes with no animation whatsoever. (00:12:27)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Other mistake: Helga and the Nanny: At the start, Miriam's dress is its usual purple colour, but when Inge arrives and walks into the kitchen, her dress is mistakenly coloured green. Her dress changes back to purple when she is shown again. (00:12:40)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Continuity mistake: Helga and the Nanny: In the shot after Helga tells the kids that her father fired Inge, Arnold's lunchbox has a baseball and baseball bat symbol on it, but two shots later, the symbol is gone. (00:19:52)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Revealing mistake: Helga and the Nanny: When Helga tells the other kids that her nanny was fired, as she says, "Yeah, well my dad found his lucky belt under her bed this morning," her left-side hair disappears for one frame. (00:20:06)
Arnold Betrays Iggy / Helga and the Nanny - S3-E10
Continuity mistake: Helga and the Nanny: After Helga tells the kids that she took her father's belt instead of Inge, Arnold tells her that he can't believe she would do something that mean, then he gets up and leaves. He is not holding his lunchbox in this shot, but his lunchbox appears in his right hand a shot later. (00:20:12)
Answer: The show is based in present day times. Plus most cars aren't old fashtioned, I recall seeing a limo and not to mention a cherry picker, etc.