Beginner needs help with Powershell script (combined with Batch)

So im new to reddit and powershell, and i need help: this is the Powershell script that i use in this batch file. What i want the powershell script to do, is to rename some files i created in the batch into something i wrote in a text file, every line in the textfile = the name of one file created by the batch, but it always says that a new file cant be created when it already exists (i dont have powershell in english, so i translated the error message, sorry for any grammar/spelling mistakes)