jielpe_fr38 there is no indication of hanging jobs in any of the earlier comments. I've not seen any mention of hanging jobs related to exceptions being written to the log. I suspect the hanging jobs in your case are unrelated to the exception message.
You should be able to resolve the exception message by correcting the browser definition for any Jenkins jobs that are configured with an AssemblaWeb browser and have an empty value for the browser URL. If the config.xml file that defines the job contains the string "hudson.plugins.git.browser.AssemblaWeb" then you need to check the value of the browser.url field. In my job definitions, it looks like this:
In the case where the exception is generated, it might look like this:
The simplest correction in that case is to remove the browser tag from the job definition, either from the Jenkins user interface or by editing the config.xml file.