So, I would suggest you to perform below steps to resolve this.
1) TFTP format and reload the device firmware, you can refer to document below
2) After that please verify whether you are still seeing the ext2 error
3) Then please make sure the AV engine status is available with version number
4) Your current firmware is an old firmware as well, I would suggest you to upgrade the unit to latest firmware. You can refer to below document on the supported upgrade path
Please ensure you backup the configuration file and read through the release notes before upgrade.
Please let me know the result. Please share your feedback. Thank you