General Support: Undefined index error on attempts to upload or import an image

I have had plogger functioning well for over a year. Then suddenly when I tried to upload or import photos I get the following error messages:
Notice: Undefined index: ftp_host in */plog-admin-functions.php on line 1238
Notice: Undefined index: ftp_user in */plog-admin-functions.php on line 1239
Notice: Undefined index: ftp_pass in */plog-admin-functions.php on line 1240
Warning: ftp_connect() [function.ftp-connect]: php_network_getaddresses: getaddrinfo failed: Name or service not known in */plog-admin-functions.php on line 1243
Warning: ftp_login() expects parameter 1 to be resource, boolean given in */plog-admin-functions.php on line 1245

I see from previous posts that others are experiencing this issue and it is cropping up on plogger sites that I googled on the web. The error also occurs when I try to create a new album. Does anyone know what the issue is and how it can be fixed? I haven't altered anything between when it last worked and now. It is installed on the typical Apache / Mysql / php server.

Thanks for any help.