Take a look at the item again:
Circling the parking lot, (A)
Dominique searched for an empty space close to the mall
entrance (B)
so that an afternoon thunderstorm wouldn't drench
her (C)
while she was loaded down with good buys.
You wanted to do this:
Circling the parking lot, Dominique searched for an empty space close to
the mall entrance so that an afternoon thunderstorm wouldn't drench
her, while she was loaded down with good
buys.
Adding a comma after her is an error. While she was loaded down with good buys is a subordinate clause. This type of clause will usually require no punctuation when it concludes a sentence.
You might want to review the rules.
Go back to the sentence to try again.