Welcome Stefan

As I understand what you are describing ... the engine stops when a load is applied?

The engine runs fine in Neutral?

The engine runs fine in First Gear with the clutch disengaged? (i.e., the bike is not moving because you are squeezing the clutch lever)

When you engage the clutch, and the bike begins moving forward, the engine stops? Is that what happens? If so, does the bike actually move the 5 meters? For example, both of your wheels turn freely, correct? (i.e., with the engine off, can you easily push the bike around, as normal?)

Are you able to fully engage the clutch before the engine stops? (probably not within a few meters)

Are you able to gently "ride the clutch" and increase RPMs to keep the bike moving forward? Or does the engine always stop, no matter how you play with the throttle and clutch?