Erdevik is a familiar place name because Sam Handler reported it to be his birth place on his 1919 naturalization papers, so I was very excited to take a look.
At the JewishGen search page for the Hungary Databases, I searched for Surname: Handler, Town: Erdevik, and GivenName: Sali. (Note that, although JewishGen is free, I make an annual donation to JewishGen, which provides me with this searching flexibility.)
The results I got include birth records for Rosi Händler, Josef Händler and Salomon Händler, to parents Aron / Adolf Händler and Sali Händler. (Yes, that is Sali's surname: see Surname Saturday ~ Handler for an explanation of their relationship.)
They were all born in the (very small) town of Ljuba. Erdevik is the town that the birth was registered in, and it is located in the District (Járás) of Ilok and the County (Megye) of Szerém.
I don't know why I don't see a record for the birth of the youngest child, Regina, but I will keep looking to see if her birth was transcribed incorrectly.
Below is a current map of the area, with Ilok, a larger town at the top, in the present-day country of Croatia; Ljuba, a very small town, shaded in pink, primarily in the present-day country of Serbia, and Erdevik, a larger town at the bottom, located in present-day Serbia. Look closely and you'll see a dark grey line which is the boundary between Croatia and Serbia.
|From Google Maps|
I have previously shared maps of the area, showing how far away Josef Handler lived from his bride, Lena Hollander. At Google Maps, searching on Ljuba, Serbia, and selecting Google Earth view, you will see user-uploaded photos of the area across the bottom of the screen. This is where the Handlers were from!