New to scripting, need help on error "scalar assignment"

Hi,
I am very new to scripting, if possible I need some help:
Here is an edited script that I would like to retreive the counts of how many instances of a program are running.

The script will be collecting data t output to a screen, and I would like to insert the counts in the output, but I receive the error:
"Can't modify constant item in scalar assignment at ./rk7 line 11, near "`ps -ef | grep -i uvspool | grep -v grep | wc -l`;" "

Here is the partial script:
while ($repeat) {

COUNT=`ps -ef | grep -i uvspool | grep -v grep | wc -l`;

### code will go here:

if (! $pslocate) {
print " WARNING!!! *** $process *** NOT RUNNING\n";
} else {
@pslocate = split( /\s+/, $pslocate );
print " Running by $pslocate[1] \t and PID is $pslocate[2] \t $COUNT ---> $process - OK\n";
}
}


print "\n TEST : \n";
exit unless $loop;
sleep $repeat;


Thank You