Thunderbird Portable doesn't want to work anymore

I am using Windows XP SP2 and Mozilla ThunderbirdPortable on USB key

Yesterday I compact my mail-folders with Thunderbird Portable and since that I am unable to use it. I get an error message from Windows what is strange for me.
I suppress the ThunderbirdPortable folder and reinstall the software but I get the same message.
I am also surprised by the fact that ThunderbirdPortable appears in one key of the registry.
How can I solve this problem ?
Many thanks for the answer.

GBray
georges [.] bray [@] neuf [.] fr

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