Question: dsolve cannot evaluate the solution further left of %1, too many step failures, tolerances may be too loose for problem

i got loop dat gives me Vx and Vy functions in evry step,i need to solve this ode 


proc (X) options operator, arrow;
X(t) end proc;
proc (Y) options operator, arrow;
Y(t) end proc;

ode := diff(X(t), t) = evalf(subs(x = X(t), y = Y(t), subs(vvx = Vx, vvx))), diff(Y(t), t) = evalf(subs(x = X(t), y = Y(t), subs(vvy = Vy, vvy)));
ics := X(0) = xxx, Y(0) = yyy;
ds := dsolve([ode, ics], type = numeric, method = rkf45, maxfun = 0, output = listprocedure);
XX := rhs(ds[2]); YY := rhs(ds[3])

i got XX(t) and YY(t) this is one parametric function,she looks like this

[URL=http://hostingkartinok.com][IMG]http://s5.hostingkartinok.com/uploads/images/2013/11/6b7bc8537f9f8d3d37c7b30bc3c2b316.jpg[/IMG][/URL]

i need to get her 1st and last value of t when she exist.
i make XX(-9999999)  and XX(9999999) to catch erorr and get values.
but for some Vx and Vy i get  
"cannot evaluate the solution further left of %1, too many step failures, tolerances may be too loose for problem",−0.15345979       
erorr.

When he try to get XX(999999) he spends like 10-15 minuts, so its realy big waste of time , i just need to get this critical valuse,so maybe there is another way?