Error: Nonnegative width required in format string at (1)

As already answered, you need to specify widths. Something like ES14.5 might work well for the floating point format. There is a short cut for the integer format: I0 will cause the compiler to use the number of digits needed.

Try changing the format string I to Iw where w is a positive number. Same with E, only use Ew.d.
For explanation see, for example, this link: http://www.cs.mtu.edu/~shene/COURSES/cs201/NOTES/chap05/format.html

Beware though: using, say, I3 for writing out 1234 might print ***, so make sure your formats are wide enough.

EDIT: See @M.S.B.'s answer on how to avoid problems with integer formats.