Only simple tenses are accepted here (I jump, I jumped, I will jump, etc.).
Continuous tenses (I am jumping, I was jumping, etc.) are expected on this course when the Klingon has the -taH aspect suffix.
So "Klingon, I am jumping" would be accepted only for tlhIngan, jISuptaH, not for tlhIngan, jISup. (And conversely, tlhIngan, jISuptaH won't accept "Klingon, I jump".)
So is 'jI' the prefix for 'I' and 'bI' the prefix for you?
That's half of it!
Klingon verb prefixes encode not only the subject but also the object, or lack of an object.
So jI- is not merely the prefix for "subject = I" but more specifically for "subject = I, no object". Similarly, bI- is the prefix for "subject = you [one person], no object".
You couldn't use jI- if there was an object, e.g. "I see the book" or "I love you" or "I trust them". jI- and bI- are only used if there is no object, e.g. "I run, you jump, I eat, you sing, I laugh, you cry".
(Thus "I eat" and "I eat food" will have different verb prefixes, because the first sentence has no object but the second one does.)
Also, well done for writing jI- and bI- with capital i instead of lower-case L (l)!
Because the Klingon prefix system includes both subject and object, it gets a little complex. I'm guessing you haven't read the Tips. Duolingo has hidden the Tips, so I want to make sure you know about them and where to find them. If you have not been reading the Tips, I think you will find them very helpful.
If you are doing the course on iOS or Android, you cannot currently access the Tips through the app. To access the Tips, you will have to access the course using a web browser at https://www.duolingo.com/. You can still do it on your mobile device, but you will have to use the web browser instead of the app (or you can do it from a computer). When you click on a Skill, it will expand to reveal a Start button and a Tips button.
If you click on the Tips button it will show you the Tips and give you a detailed explanation of the grammar that is introduced in that Skill. If you have questions after reading the Tips for any Skills, we are happy to answer your questions, but many of your questions will probably already be answered in the Tips.
tlhIngan jISup would most likely be interpreted as, "Klingon! I jump." In the example sentence, we added a comma to make it clearer for beginners, but the comma is not reuired and it means the same without it.
The use of the jI- prefix means that there is no object and tlhIngan has not been marked in any other way to make it part of the sentence, so it would be interpreted as an exclamation. Klingon does not have something like the preposition "over" and does not have a single verb that expresses something like "jump over".
In a case like this it is probably best to use two sentences, one saying that you jumped and one saying that you went over the person or thing: jISup 'ej tlhIngan Dung vItol. "I jumped and passed through the area above the Klingon."
It seems like tlhIngan Dung vISup could mean I jumped over the Klingon. If it doesn't mean I jumped above the Klingon. There are quite a few sentences that would require a similar structure. I walked over the hill. I drove over a kerb. I ran across a (battle)field. I jumped a wall. Hopefully a less awkward solution will be forthcoming! Edit: corrected spelling
I'm pretty sure that Sup doesn't take an object. You don't "jump something" in Klingon, you just "jump". If you want to say you jump "into" something" or "over something" or "using something", you need to provide additional explanation. No less awkward solution is needed. Different languages express things in different ways.