It maybe an issue where your handheld sevice is running out of disk space.

How to check disk space status:

Start > Settings > Memory

Here you see the amount free.

If amount free is close to zero then your device is full.

Dont forgot to check your storage card.

Also there is a option at the bottom of the memory page to find large files. 

Possible solutions:

Deleting any music and pictures.

Start > Programs >File Explorer

To delete files, click and hold the files until the dropdown box appears and simply hit delete.