Ultimate-Branding : Warning: preg_replace() [function.preg-replace]: Unknown modifier'

Problem regarding "Ultimate Branding".

Error message :
Warning: preg_replace() [function.preg-replace]: Unknown modifier'/' in /..... on line 377

Descritpion :
I installed "Ultimate-Branding" plug'in and I used "Network Wide Text Change" module to search and to replace a tag url ... and I have an error message about 1500 identical lines :
Warning: preg_replace() [function.preg-replace]: Unknown modifier'/' in /..... on line 377

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I deleted the plug'in and I reinstalled it.
I desactived all plug'in and I changed the permalink (in wordpress>setting>permalink) and I have got always the same error message.

Could you give me the procedure to be followed to re-use "Ultimate-Branding" without any problem.

Thank you for helping me.
Best regards