I really need help (all messed up for a language change)

Hi,
I'm new to Joomla. I've installed uddeim and adjusted all the options for about 1 hour...worked wonderfully...like a charm! Then I tried to change some strings of language (following the instructions in the FAQ) and ALL is messed up! Suddenly I couldn't enter in the profile page nor in the "inbox" of uddeim...just an horrifying blank page with no error messages!!!
I've tried debuggin, that's what happened when I tried to enter profile page:



Now, when I disable "Private Messaging System (uddeIM PMS)" (from CB Tab Manager) and all related plugins, the profile page returns to work correctly (eccept, obviously for the messaging system which is not active).

I've tried replacing the original file to \administrator\components\com_uddeim\language.utf8
but nothing changes.
I think that's the problem is related to the fact that previously I modified the "_UE_PMSLINK" tab name. But uninstalling and reinstalling all the CB uddeim plugins doesn't work...I can't figure it out...I don't want to delete the main component of uddeim because I've spent a lot of work on it...and I am not sure it would work...
Could you help me please?
Thanks in advance...

You have two problems:

1. You have messed up the CB language file (two constants are defined twice) - this error might have been present in the italian language file, since it is a notice only you can ignore it (it should be fixed nevertheless)

2. You have definitely messed up uddeIMs language file. Unpack com_uddeimXXXX.zip and upload the original file using ftp or a component like explorer.

When you plan to change a language in utf8 use an editor that can handle it, e.g. Notepad++. Do not use Windows Notepad to change the file.

1 - I don't know how to fix it but I might check it later.

2 - I've exactly used Notepad++ ! I don't know why that messed up anything!
In addition, replacing the original Italian.php file with filezilla doesn't work...

Could I fix it uninstalling uddeim and reinstalling it?

Any suggestion?

UPDATE: The issue it's definitely related to the language file. Uninistalling and reinstalling brings back everything ok. Uploading a modified language file breaks all the pages related to uddeIM.
A question remains...since uploading the original file doesn't work, how am I supposed to modify the *.php files language?
Just saving in Notepad++ it's not a working solution.
Thanks.

Don't use the ASCII mode to upload the files. Utf8 requires that the files are uploaded binary.

Thank you. I'll give it a try and I'll let you know!