There is a high probability your computer antivirus / malware program is interfering with Music Creator 7 operation. Even if you've excluded the program from scanning the Music Creator directories the program may be too aggressive at preventing writes to the hard drive.
Another probable cause might be the hard drive data is highly fragmented preventing hard drive writes to be performed in a timely manner.
Last, the computer hard drive may not have enough free space left to store the audio file.