英语教师王太来回答吧.
这句话完全正确.
它的主语是：Alle's not being able to accomplish the mission 埃里不能完成这项工作
它的谓语是：eventually contributed to 最终造成了
它的宾语是：his being disqualified from maintaining his position 他不能继续留任.
上面的句子没有独立主格.请看下面的句子：
The weather was very cold, so we had to stay home. 这是一个主从复合句,主句是The weather was very cold; 结果状语从句是so we had to stay home; 其中第一句话可以改成独立主格,既把动词was 改成being,句子就成了：The weather being very cold, we had to stay home.
又如：Having fishined his homework, Jack went home. 在这句话的基础上写一个独立主格的句子,就可以写成：Jack's having finished his homework, his parents allowed him to go out. 杰克完成作业之后,他的父母才让他出去玩.
我们可以这么说,独立主格有三大特点：第一,它含有现在分词； 第二,这个现在分词含有一个逻辑主语；第三,它在句中作状语.你写的句子之所以不是独立主格,就是因为他们不做状语,而是分别作主语和宾语.
somebody doing something =somebody's doing something, 没区别,但是有使用习惯.
说明：我只是根据你的困惑,讲了独立主格的一种形式,希望能对你有所帮助.