error in time dependent study

hello
for study: range(35,0.1,95)
i am getting error: Failed to find consistent initial values.
Segregated Step 2
Attempt to evaluate real square root of negative number.
Function: sqrt
Failed to evaluate expression.

and study for range(35,0.1,70) is running fine.
and this study don't have any time dependent expression.
can anybody suggest something.

regards
Vishal Goyal