Generating extract structure

Hi,

I am trying t o generate an extract structure, i give in the table name and execute it and a wondow pops up " ADD DEVELOPER" i go into the information and it says

"<b>you need an acess key for each developer in the system. this key has to be enterd only once. TO modify any object in SAP you need an acces key. If an object is registerd it can be modified by all deveopers in the system. Connect to the r/3 OSS her you can get access key to the development users and objects"</b>

What does this mean.