Cannot access forms fronm the back end

I cannot acces forms from the back end, I just see a page without css and links are not working
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Hi l.villa,
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You may have a PHP Error on the page, please try setting Site Error Reporting to Maximum temporarily and see if you get a more helpful error message.
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Bob

I tried, the only error I can see is:
<b>Fatal error</b>: Class '\GCore\Admin\Extensions\Chronoforms\Fields\Common.\Common.' not found in <b>/home/hsole/hotelsole.com/administrator/components/com_chronoforms5/chronoforms/views/edit.php</b> on line <b>1263</b><br />

Hi l.villa,
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The problem is that Common. = in this code CF is identifying the type of input e.g. checkbox, dropdown, file . . . and Common. is not a valid type.
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I can't tell from here where that is coming from, maybe some Custom Code in the form?
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Bob

Hi l.villa,
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Please try to download the latest v5 installer and install it OVER yours, does this help ?
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Best regards

I instelled the latest v5 but this doesn't hepl. I have the same error in all the forms, even if I try to make a new form from scratch
Thanks
Luca

Hi Luca,
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Please try to find if there is a folder called "common" under this path:
/home/hsole/hotelsole.com/administrator/components/com_chronoforms5/chronoforms/fields/
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Best regards,
Max

No, there's not a folder "common" under this path

Hi Luca,
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Same error when you try to create a new form ?
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Best regards,
Max

Yes, same error

Any help?

Any reason you can't just move to v6?

Do I need to rebuild the forms or there is a migration tool?

Are they really complex forms?