I am just guessing the meaning: “I may be mistaken”. Is this correct? (literally “I may know the wrong thing”. Perhaps I am totally wrong. Yardımınız için teşekkür ederim 
This is Indefinite Past Tense Continuous Inferential Form.
This form is used to give the sense of inference. Please note that there is a doubt in what we are saying.
bil-iyor-muş-um
“Ben yanlış biliyormuşum” means
It seems (1. they say / 2. I’ve just realized) I’m wrong.
Geliyormuşum.
It seems(…) I’m coming.
Thanks a lot. So I wasn’t totally wrong.
“I may be mistaken” has a similar meaning to “It seems I’m wrong”, but not quite. Your explanation was very helpful. Perhaps one could also use the perfect in English: I seem to have been wrong or It seems I have been wrong.