.zshrc is a file run when you start an interactive zsh shell, found in your home directory. The error message says you have an export command which is written incorrectly on line 48.
not valid in this context means you're trying to export something that's not a variable. It looks like you're trying to add stuff to your PATH, but are substituting the current path inside the zshrc file. Check that line in the file, there's probably a line along the lines of:
You just need to remove the first
$ because it's substituting the current path there instead of assigning the PATH variable: