I solved my issue. I went into file manager. I told it to show hidden files. I found a strange twc.err file on my SD card. I wasn't sure what it was so I googled it. Someone on another forum was asking what the file was and that they were getting a low volume space error and they hardly had anything on their phone. Someone replied that they didn't find a whole lot about it but other people had the file and deleted it with no repercussions and it solved their issue. So I deleted that file, and now all of a sudden I am able to transfer files to my SD card! Really odd! Not sure why that kind of file would prevent me from saving apps to my SD card as it's not a system file. But thought I'd post in case anyone else had the same issue.
Mel