If you turn on the Context Help (and you should probably have it on whenever you are developing or troubleshooting code), it will tell you what is wrong with a wire when you hover the wiring tool over the broken wire.
In your case is says you have wired two sources to one sequence local, which you have. In frame zero you connect a string to the local. In frame one you have the "new file path" output from the Write to Spreadsheet File connected to the same local. In any frame after the one where you first wired something to a sequency local, the local is read-only.
And, as Dennis mentioned, there is no need for that sequence structure at all.
Lynn