Hi,
the client tries to import the certificate into the Java runtime. You use an user created certificate, therefore, this import is needed.
It seems that your computer/settings/user profile does not allow to change this file. You might not be administrator or you simply do not have the access rights.
If accessing this file is not possible, the administrator should place the file "cacerts", enriched with the certificate on the server. Location:
<server install dir>\server\bin\work\work_abs_<s|m|l>\base\webapps\abs\downloadClient\config
If the file is placed there and is properly enriched with the certificate, importing is not necessary.
Bye,
Frank