[function.unserialize]: Error at offset

I initially came across this error while I migrated my site from local server to live server.
Notice: unserialize() [function.unserialize]: Error at offset 83 of 108 bytes in variable_initialize() (line 935 of /home/ebemorgi/kog.church/includes/bootstrap.inc).

I followed #9 from this drupal post but I found out that
the variable causing the issue was authorize_filetransfer_connection_settings_ftp.

I deleted the above variable but that hung up my whole website.

Then I deleted the content in the variable table and re-populated it.
Initially the error didn't popup but when I tried installing a new module at the live server the error
popped up with an new offset value. Again the villain is authorize_filetransfer_connection_settings_ftp.
The error which I am now receiving is :
Notice: unserialize() [function.unserialize]: Error at offset 32 of 121 bytes in variable_initialize() (line 935 of /home/ebemorgi/kog.church/includes/bootstrap.inc).

I have made sure that I have updated the ftp details in my mysql dump file before importing it to live DB.

I'm not sure if this issue is related to Core, but I don't honestly know under which product to list it.

Any help is appreciated.