CPU idle% "is zero"

We’re running cloverleaf 5.7 on RHEL  (5.x, can’t remember which point version), and after about 90 days of uptime we’ll get an alert that idle% is zero, which also likes to crash the monitor daemon.

/opt/quovadx/qdx5.7/integrator/bin/top lists (for example)

CPU states:  9.6% user,  0.0% nice, 15.5% system,  0.0% idle, 74.9% iowait

while

/usr/bin/top lists

Cpu(s):  1.3%us,  1.7%sy,  0.0%ni, 86.1%id, 10.8%wa,  0.0%hi,  0.0%si,  0.0%st

Cloverleaf top is version 3.6, and ldd outputs:

linux-gate.so.1 =>  (0x009fa000)

libm.so.6 => /lib/libm.so.6 (0x009b1000)

libtermcap.so.2 => /lib/libtermcap.so.2 (0x00c3d000)

libelf.so.1 => /usr/lib/libelf.so.1 (0x00b06000)

libc.so.6 => /lib/libc.so.6 (0x00856000)

/lib/ld-linux.so.2 (0x00837000)

RedHat top is procps version 3.2.7, and ldd outputs:

linux-gate.so.1 =>  (0x00cb2000)

libproc-3.2.7.so => /lib/libproc-3.2.7.so (0x009b1000)

libncurses.so.5 => /usr/lib/libncurses.so.5 (0x04e3f000)

libc.so.6 => /lib/libc.so.6 (0x00856000)

libdl.so.2 => /lib/libdl.so.2 (0x009dc000)

/lib/ld-linux.so.2 (0x00837000)

Has anyone else seen this before, or have an idea what causes it?  Other than rebooting the server does anybody know what could help fix this?