>My question then is, for those who have English as mother language:
>Is it wrong to say "I saw her stand there" in English?
>I certainly think (B') is incorrect Old Norse.

That is perfectly good English, but the meaning is slightly different.

in (A)" I saw her standing there." there is nothing to indicate that 'she'
is not standing there still. We cannot know if she is still standing there
or not without further clues from the context.

in (B) "I saw her stand there." it is implied that she is no longer standing
there, but while she was doing so, I saw it happen.

You cannot say, "I saw her stood there." -- You would have to break it into
two cluses, or add a preposition and a personal pronoun: "She stood there; I
saw her" or "I saw her as (while, when, etc..) she stood there."

The infinitive and the gerrund (the -ing) can often be used interchangeably,
usually with a slight shift in implication. Only the gerrund form of a verb
can be used alone as a noun. "Standing there has occupied a lot of her time
lately."

Dæg