fme_in = open(self.filename1, 'r')

self.filename = tkFileDialog.askopenfilename

replacements = {'%p%':self.filelocation.get(),'%r%':self.filelocation1.get()}
for line in fme_in:
 for src, target in replacements.iteritems():
   line = line.replace(src, target)
 fme_out.write(line)
fme_in.close()