Solution: This problem usually happens when there is an existing version of
MegaBrowser on your computer and the existing version is too old.

First completely remove the old MegaBrowser client from your computer
and from your registry. Then re-install the newer version from scratch.

How to remove MegaBroswer:
To remove MegaBrowser, you  need to shut down MegaBrowser Winsock2 DNS addon.

How to proceed:
-remove link to MegaBrowser client from startup;
-remove reference in Winsock2 service in registry
(please go to
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\
    Parameters\NameSpace_Catalog5,
    decrease by one the value of Num_Catalog_Entries, then go to
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\
    Parameters\NameSpace_Catalog5\Catalog_Entries
    and remove entry that have reference to MegaBrowser.
    Usually this is the entry with name 000000000003 )
- reboot your computer
- remove (completely) directory with MegaBrowser