Are you still researching this family?
It appears your Wojciech Popek arrived in New York City, aged 17, on April 18, 1910 from Antwerp aboard the SS Lapland. He was coming to join his brother-in-law Wojciech Popek in Passaic, New Jersey. He was born in Mazury.
Interestingly enough, there was a Wojciech Popek who arrived in New York City, aged 22, on April 13, 1904 from Bremen aboard the SS Bremen, to join his brother Josef Popek in Passaic. He was born in Mazury.
I have a Eva Bialas, age 18, arriving in New York City on Feb. 16, 1910 from Antwerp aboard the SS Lapland, daughter of Marcin Bialas (and mother Marianna Popek, per a tree on Ancestry.com) going to join her step-brother Wojciech Popek in Passaic. She was born in Mazury.
Are you familiar with all these folks, and can you sort this out for me?