We just had our harddisk restored by theplanet and installed original master as second drive. We suspect a damaged filesystem on the second drive and can not access it. FSCK did not work.

Do you know of any utilities and tools for data recovery on linux server that can be remotely installed on the linux web server and run from the command line (not windows based or solutions that require a graphical terminal)?

Do you have any other tips and hints we can try to restore the data under these circumstances?

Well if you can arrange a windows based system and installed your infected hard drive as a slave and run the Stellar Phoenix Linux Data recovery software. Hope it would help you to recover your lost data.
Stellar Phoenix Linux - is a fully automatic Linux data recovery software for Ext2 and Ext3 File system volumes. It uses a unique scanning method, which automatically recognizes lost partitions,volumes, files and folders. The software provides Linux data recovery from IDE/EIDE/ATA & SCSI hard drive media.
Only limitation with this software is that it runs on only windows based system.

To try the software download the demo version from: http://www.stellarinfo.com/linux-data-recovery.htm