@Markiyan Hirnyk Quite correct. Notice the closing remark in my answer.

@Carl Love I got the same error.
I just tried to isolate the highest derivatives:
solve({Eq1, Eq2, Eq3, Eq4},diff~({f,theta,h,g}(eta),eta,eta));
## That suggested using a midpoint method (  sqrt(diff(f(eta), eta)) being in the denominator):
dsolve(eval(dsys,lambda=0), numeric,method=bvp[midrich]);
## which didn't solve the problem.
## The imaginary I may come from the sqrt in  sqrt(diff(f(eta), eta)) (I changed nn from 1.5 to 3/2).
## I shall have another look in a few hours.

The multiplication operator in Maple is * not . (dot). So begin by changing all those dots to *.
After that you still have a problem.
I suggest omitting continuation in lambda until you have a problem that only suffers from convergence issues.

@mskalsi If you are using Windows try unzipping the mla file to:

"C:/Users/xxxx/maple/toolbox/DifferentialGeometry"

You need to replace xxxx with the name of the user (presumably you). Don't change anything else!

Then in the worksheet supplied by Ian Anderson (Optima1.mw) start with

restart;
libname := "C:/Users/xxxx/maple/toolbox/DifferentialGeometry", libname;
### Then continue with
with(DifferentialGeometry);
## as in the worksheet.
## Using that location should ensure that the help also works: Try
?DifferentialGeometry
## I just downloaded and tried the above with xxxx=Bruger (which happens to be my username on this computer). It worked.

@acer I tried evalindets in Maple 2016 and also in Maple 2015.2:

restart;
A := [ [2,3], [4,5] ,[6,7]];
#indets(A,list(realcons));
evalindets(A,list(integer),(`/`)@op); #OK
evalindets(A,list(realcons),(`/`)@op); # Surprise: 35/36
#That result seems to be the result of recursing as in:
evalindets(A,list(integer),(`/`)@op);
evalindets(%,list(realcons),(`/`)@op);
###
## Doing the same in Maple 18.01:
evalindets(A,list(realcons),(`/`)@op); # [2/3,4/5,6/7]

### Were the changes to evalindets made in Maple 2015 intended to have this recursive effect or is this a bug?

With the same A and an unassigned f:
evalindets(A,list(algebraic),f);
## In Maple 2016 and 2015:  f([f([2, 3]), f([4, 5]), f([6, 7])])
## whereas in Maple 18:  [f([2, 3]), f([4, 5]), f([6, 7])]
So it seems recursing is being done since 2015.
## Can it be prevented? Or is it a bug?
## I shall submit a bug report just in case ... .

Do I understand you correctly: You want to do some symbolic manipulations in Maple (maybe turn the system into a first order system) and then use Matlab to do the numerics?

If so you could use DEtoools[convertsys] in Maple to get a first order system. But why not start with doing the whole thing in Maple and let it worry about the conversion?

@nrebman1 Take a close look at the output from

diff(x[0, 1](t), t, t) = force(0)[1];

What did you expect on the right hand side?

There was an answer by Kitonum:

http://www.mapleprimes.com/questions/211685-Intersection-Of-Real-Intervals

@torabi Quite right. I overlooked that Q[4,2] is a sum:
200.*Y-2/(0.1e-1*y+.11)

thus won't be dealt with by py.
Hopefully this one works as intended:

px:=proc(u1) global X,x; local u:=expand(u1);
  if type(u,`+`) then return map(procname,u) end if;
  if not type(u,`*`) then return u end if;
  if member(X,{op(u)}) then diff(u/X,x) else u end if
end proc;
py:=subs(X=Y,x=y,eval(px));
pz:=subs(X=Z,x=z,eval(px));

@iman The problem is that all the highest derivatives are in the first equation.

You can solve that by doing:

sys:=select(has,dsys4,diff);
solve(sys,{diff(phi(x),x$3),diff(u(x),x$3),diff(w(x),x$4)}); #Cannot be done
##Now differentiate:
sys2:=diff(sys[2],x);
sys3:=diff(sys[3],x);
bcs23:=subs(x=0,convert(sys[2..3],D)); #New additional boundary conditions
sysnew:={sys[1],sys2,sys3}; #The new system
solve(sysnew, {diff(phi(x),x$3),diff(u(x),x$3),diff(w(x),x$4)}); #Now successful

@Jean-Michel Collard Although I probably won't have the need for using the CUDA capabilities (if any) of my computer I tried your example (i.e. the one from the help page) on my computer.
I got the same error message as you did.
At the same time a message came up from the graphics driver that it had stopped working.
I have NVIDIA GEFORCE GTX 860M version 364.72 on a 64 bit machine with Windows 10 and use Maple 2016.1 (64 bit).
Going to the NVIDIA page to look it seemed that it ought to have worked, but what do I know?
##
Just tried in Maple 2015.2 (64 bit) on the same machine: Same result.

I guess I don't need to tell you that you should avoid 2D math input as the plague!

Use 1D math input aka Maple input.

Well, if your ode system is 'secret' how do you imagine that we can help you?

This site is dedicated to questions about Maple.

@acer To check your result I tried an iteration approach treating the integral as a perturbation, but not replacing Int with anything else.
First letting f3(x) be zero in the integral, producing a result res[0]
Inserting the newly found f3 into the integral, compute again to find res[1], etc.
I stopped after 8 iterations with res[8].

The maximal differences between the results res[8] and your sol were:
9*10(-12), 5*10^(-13), and 5*10^(-9) for f1, f2, and f3, respectively.
The differences were larger for res[i] with i < 8, which seems to confirm that your result sol is pretty good.