RStan installation failure, R 3.4.2 on 64-bit Windows 10

Hi
I am trying to use Rstan for the first time.
I am using R 3.4.2 and have used Rtools34.exe for installation of Rtools. I am following the instructions from this page:
https://github.com/stan-dev/rstan/wiki/Installing-RStan-on-Windows

Under the section "Verify that Rtools can be used in R", I run into problems. When running the commands given in the section, I get the following message:

Warning message:
running command 'make -f "C:/Users/a3988/DOCUME1/R/R-341.2/etc/x64/Makeconf" -f "C:/Users/a3988/DOCUME1/R/R-341.2/share/make/winshlib.mk" -f "C:\Users\a3988\Documents/.R/Makevars" SHLIB_LDFLAGS='$(SHLIB_CXXLDFLAGS)' SHLIB_LD='$(SHLIB_CXXLD)' SHLIB="file30c461073925.dll" WIN=64 TCLBIN=64 OBJECTS="file30c461073925.o"' had status 127

ERROR(s) during compilation: source code errors or compiler configuration errors!

Program source:
1:
2: // includes from the plugin
3: #include <R.h>
4: #include <Rdefines.h>
5: #include <R_ext/Error.h>
6:
7:
8: // user includes
9:
10:
11: // declarations
12: extern "C" {
13: SEXP file30c461073925( SEXP x, SEXP y) ;
14: }
15:
16: // definition
17:
18: SEXP file30c461073925( SEXP x, SEXP y ){
19:
20: return ScalarReal( INTEGER(x)[0] * REAL(y)[0] ) ;
21:
22: Rf_warning("your C++ program does not return anything");
23: return R_NilValue ;
24: }
25:
26:
Error in compileCode(f, code, language = language, verbose = verbose) :
Compilation ERROR, function(s)/method(s) not created! Warning message:
running command 'make -f "C:/Users/a3988/DOCUME1/R/R-341.2/etc/x64/Makeconf" -f "C:/Users/a3988/DOCUME1/R/R-341.2/share/make/winshlib.mk" -f "C:\Users\a3988\Documents/.R/Makevars" SHLIB_LDFLAGS='$(SHLIB_CXXLDFLAGS)' SHLIB_LD='$(SHLIB_CXXLD)' SHLIB="file30c461073925.dll" WIN=64 TCLBIN=64 OBJECTS="file30c461073925.o"' had status 127
In addition: Warning message:
running command 'C:/Users/a3988/Documents/R/R-3.4.2/bin/x64/R CMD SHLIB file30c461073925.cpp 2> file30c461073925.cpp.err.txt' had status 1

I am using the following:
R Version: 3.4.2
RStan Version: 2.6.12
Rtools: Rtools34.exe
OS: Windows 10

I would really appreciate some guidance.

Start with the RStan Windows installation wiki section named “Verify that Rtools can be used in R,” using the reported R 3.4.2, RStan 2.6.12, Rtools34, and Windows 10 versions. Reproduce the commands and inspect the status 127 compilation output; the issue is resolved when the verification succeeds or the configuration cause is identified.