Do you have a save before you picked up the 4 rope you need? The easiest solution would be to make sure you drop any other rope first. If not, you can split a stack up by dragging and dropping it somewhere (between inventory and the ground, or different inventory windows) and holding the ctrl key down before releasing the mouse button. A split stack window will open, where you can select how many to move. You may have to experiment a bit to find the correct 2 rope (IIRC with the 4 rope, 2 stack together and 2 are separate).
Alternately, further down in the 'inventory files' topic is a 'Silver armour upgrade' set of inventory files, which contain the 4 rope as well as everything else required to enter the easter egg area. Rather than dropping the replacement rope on the ground, you could just load the save with the those inventory files, step on the teleporter to get to the easter egg area, save the game under a new name, restore your original inventory files, and keep playing.
There is not much experience in this area, just the upgrade for the silver armour; it is not important for the rest of the game.
