My html webpage calls php script to upload files to the server from a local computer as follows.

<form enctype="multipart/form-data" action="upload.php" method="POST">
<p><b><h3>  <font color="#003366"> (1) Upload your reading text file.  </font> 
</h3> </b> </p>
<INPUT type="file" name="uploaded" size="50" >
<br/>
<input type="submit" name="files" value="upload">
</form> 

In order to process with an uploaded file, my php script calls shell script

$output=system('/bin/sh connector_0.sh');  

and my shell script is composed of a series of python/perl scripts.

#!/bin/sh

python main_senselearner_final_0.py 

senseLearner.pl -i Uploaded_Files/slinput_0.txt -o Uploaded_Files/presloutput_0
.txt -model modelNNCollocations -model modelJJCollocations -model modelVBColloc
ations -pos

python smutngslout_0.py 

python genhtml_0.py 

Now, the problem is the following: all python scripts in shell script worked fine through php. But perl script didn't work.

When I run shell script by myself in my server, all four scripts in shell worked perfectly. However, when I run shell script from php, only perl script doesn't work.

Would you please give me any tips to solve this problem?

Many thanks!!!