[gollem] can't download files in gollem

[Service Informatique IF]

Hello,

I have gollem 3.0.2 with H5.(ubuntu 12.04)

I can list the files on my ssh server.
I can create a directory or upload a file.
I can edit a text file, but when i want to download a file from gollem, 
nothing happens,
If I put a maximum execution time, i Have "
"PHP Fatal error:  Maximum execution time of 30 seconds exceeded in 
/usr/share/php/Horde/Mime/Part.php on line 1838, referer: 
https://......./gollem/manager.php?backend_key=ssh2


How can I debug this ?

Thanks
Sim