copy paste on transparent layer

[denzjos]

I solved it by pasting the copy the information on the transparent layer
- made the floating selection a layer
- select the copy information with the fuzzy select tool
- select the transparent layer
- erase the information on the transparent layer
- merge the two layers
Use the selection (marching ants) from the copy on the transparent layer to erase the existing information didn't work for me.  
Maybe there is a better way to do this.
Thank you for the answer rich.