Egyptian Fractions are fractions expressed in the form of 1/n or as the sum of such fractions (1/a + 1/b + ...). For example, 2/3 would be expressed as 1/2 + 1/6.
(As found on the Rhind papyrus, 2/3 was one, if not the only, non-unit fraction used by the Egyptians.)

The following Egyptian Fractions correspond to the fractional portion of the first ten non-integer members of a "regular" series. (The "whole number" component of each member of the series is omitted and any series members without fractional components is likewise omitted).

What is the missing fraction in this sequence?

1/2 + 1/14
1/4 + 1/44
1/4 + 1/18 + 1/468
1/4 + 1/28
1/2
1/2 + 1/4 + 1/14 + 1/476
1/19
1/2 + 1/3 + 1/42
1/2 + 1/8 + 1/88
1/3 + ?

Actually your thoughts were right. According to the solution, the fourth line should read 1/4 + 1/28 instead of 1/4 + 1/128

Also, don't forget that integers in the sequence have been omitted.