Incompatible versions of luatex problem

When I run the code below, I get an error about

 Package ifluatex Error: Name clash, ifluatex is already defined.

Oddly, it says the error is on line 174, but there are not that many lines in the code. I get the same error with the imakeidx package.

I am not using luatex at all, and don’t know where that came from.

MWE starts here.

documentclass[11pt, statementpaper]{memoir}
% letprovidelengthrelax
title{Interesting words}
author{Peter Flom}

 usepackage[columns=3]{idxlayout}

%usepackage{imakeidx}[2012/05/09]
%makeindex[columns=3]

%% A convenience command, for typesetting the
%% word and pronunciation

%newcommand{entry}[2]{medskipnoindent{Largetextbf{#1} (#2)par}}
newcommand{entry}[2]{medskipnoindent{Largetextbf{#1} normalsize{#2} par}}



%newcommand{sclabel}[1]{normalfontscshape #1}
newcommand{sclabel}[1]{leavevmode{normalfontscshape #1}}
%% Less spacing around lists
firmlists

newcommand{quotesep}{rule{3in}{1pt}{hfill}}

newcommand{quotefull}{epigraphwidth 3.5in
             epigraphrule 0pt}


%From https://tex.stackexchange.com/questions/182869/typesetting-a-dialogue-paragraphs-or-something-else
newenvironment{dialogue}{list{}{itemsep=parskip topsep=parskip parsep=parskip}}{endlist}

makeindex

begin{document}


printindex

bibliography{c:/writing/references}
bibliographystyle{plain}

end{document}

EDIT I am using MikTeX 2.9.

EDIT here is the log file

4"
Startup Folder: C:Writing

This is BibTeX, Version 0.99d (MiKTeX 2.9.6100 64-bit)
The top-level auxiliary file: MWEAug14.aux
I found no citation commands---while reading file MWEAug14.aux
I found no bibdata command---while reading file MWEAug14.aux
I found no bibstyle command---while reading file MWEAug14.aux
(There were 3 error messages)


Command Line:   makeindex.exe "MWEAug14.idx"
Startup Folder: C:Writing

This is makeindex, version 2.15 [MiKTeX 2.9.6100 64-bit] (kpathsea + Thai support).
Scanning input file MWEAug14.idx...done (0 entries accepted, 0 rejected).
Nothing written in MWEAug14.ind.
Transcript written in MWEAug14.ilg.


Command Line:   pdflatex.exe --interaction=errorstopmode --synctex=-1 "MWEAug14.tex"
Startup Folder: C:Writing

This is pdfTeX, Version 3.14159265-2.6-1.40.17 (MiKTeX 2.9.6100 64-bit)
entering extended mode
(MWEAug14.tex
LaTeX2e <2016/03/31> patch level 3
Babel <3.9r> and hyphenation patterns for 75 language(s) loaded.
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatexmemoirmemoir.cls"
Document Class: memoir 2020/03/25 v3.7k configurable book, report, article docu
ment class
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericiftexiftex.sty"
) ("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatexmemoirmem11.clo
") ("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatextoolsarray.sty
")
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatextoolsdcolumn.sty"
)
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatextoolsdelarray.sty
")
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatextoolstabularx.sty
") (C:UsersPeterAppDataRoamingMiKTeX2.9texlatextextcasetextcase.sty))

("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatexidxlayoutidxlayou
t.sty"
(C:UsersPeterAppDataRoamingMiKTeX2.9texlatexetoolboxetoolbox.sty)
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatexoberdiekkvoptions
.sty"
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texlatexgraphicskeyval.st
y")
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericoberdiekltxcmds
.sty")
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericoberdiekkvsetke
ys.sty"
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericoberdiekinfware
rr.sty")
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericoberdieketexcmd
s.sty"
("C:UsersPeterAppDataLocalProgramsMiKTeX 2.9texgenericoberdiekifluate
x.sty"

! Package ifluatex Error: Name clash, ifluatex is already defined.

See the ifluatex package documentation for explanation.
Type  H <return>  for immediate help.
 ...

l.174     }
           %
? x
No pages of output.
Transcript written on MWEAug14.log.

END OF LOG FILE

I have to go out, I will look at this more tomorrow