MRTG memory monitoring problems ~

MRTG memory monitoring problems ~ -- Linux Enterprise Application-Linux server application information. For details, refer to the following section. I set up MRTG and want to monitor the memory ~ However, the result shows that the device cannot be found? Why? I don't know why. Please help me. Hey hey... Thank you.

Memory Usages
Last Statistical Update Time: 2008 August 1, November 15, Saturday,
Device Name 'unknown ', operation time (UPTIME):, 1 user ,.

1 'create a script with the following content. The permission is correct.
Vi/etc/local/apache2/htdocs/mrtsh-/ mrtg. memory
#! /Bin/bash
# Run this script to check the mem usage.
Totalmem = '/usr/bin/free | grep Mem | awk' {print $2 }''
Usef8 = '/usr/bin/free | grep Mem | awk' {print $3 }''
UPtime = '/usr/bin/uptime | awk' {print $3 "" $4 "" $5 }''
Echo $ totalmem
Echo $ usedmem
Echo $ UPtime


2 'the following section is added to mrtg. cfg.
Target [memory]: '/usr/local/apache2/htdocs/mrtsh-/ mrtg. memory'
MaxBytes [memory]: 4096000
Title [memory]: Memory Usages
ShortLegend [memory]: &
Kmg [memory]: kB, MB
Kilo <memory]: 1024
YLegend [memory]: Memory Usage:
Legend1 [memory]: Total Memory:
Legend2 [memory]: Used Memory:
LegendI [memory]: Total Memory:
LegendO [memory]: Used Memory:
Options [memory]: growright, gauge, nopercent
PageTop [memory]: Memory Usages