The GE TMR instructions are designed to use 3 consecutive INT registers. Using DINT and DWORD data types may be causing you problems, or, as Steve indicated, if any of those registers are used anywhere else in the program.
From the GFK0467M 9030 Instruction Set manual:
Use care if you use the same address for the function’s PV (Preset Value) input
parameter as the second word in the three-word block. If PV is not a constant,
the PV input normally is addressed to a different memory location than the
second word. Some programmers choose to use the second word address for the
PV input, such as using %R0102 when the three-word block starts at %R0101.
This allows an application to change the PV while the timer or counter is
running. Applications can read the first (CV) or third (Control) words, but the
application cannot write to these values, because if they were written to, the
function would not work