I received the same error when trying to open that file.
Here is a sample script to use replacedatasource of an SDE connection
import arcpy
import os
arcpy.env.overwriteOutput=True
###test create connection file and replace data source####
SDE_file_path = r"C:\incidents\xx"
Directory_Search = r"C:\incidents\xx\mxd"
#SDE_file_path = r"\\miaoer\newMXD"
arcpy.CreateArcSDEConnectionFile_management(SDE_file_path, "testsde.sde", "user", "sde:oracle11g:orcl", "", \
"DATABASE_AUTH", "sde", "sde", "SAVE_USERNAME", "SDE.DEFAULT", "SAVE_VERSION")
print "done creating ArcSDE connection file!"
for root, dirs, files in os.walk(Directory_Search):
fListLength = len(files)
for f in files:
print "\n\n"
print fListLength
fListLength = fListLength-1
if (f.endswith(".mxd")):
#problem_File = check_File(f)
full_path = root + "\\" + str(f)
print full_path
mxd = arcpy.mapping.MapDocument(full_path)
dfs = arcpy.mapping.ListDataFrames(mxd)
for df in dfs:
for lyr in arcpy.mapping.ListLayers(df):
lyr.replaceDataSource(SDE_file_path +r"\testsde.sde", "SDE_WORKSPACE")
print lyr.name
#mxd.saveACopy(SDE_file_path +r"\testNew.mxd")
mxd.save()
print "finish replace data source"
