MRTG: Reload Ok file on Ubuntu Server

I had a problem with an MRTG server while graphing the interface use on a Cisco 2600 & another 2800 router, out of the blue, the MRTG started to graph a completely pegged interface, and printing errors such as this when "executed by hand" from the CLI:

WARNING: Can not determine ifNumber for xxxx@XXX.XXX.XXX.XXX:       ref: 'Name'     key: 'Et0/0'
WARNING: Can not determine ifNumber for xxxx@XXX.XXX.XXX.XXX:       ref: 'Name'     key: 'Se0/0'
WARNING: Can not determine ifNumber for xxxx@XXX.XXX.XXX.XXX:       ref: 'Name'     key: 'Se0/0.240'
ERROR: Target[XXX.XXX.XXX.XXX_et0_0][_IN_] ' $target->[1]{$mode} ' did not eval into defined data
ERROR: Target[XXX.XXX.XXX.XXX_et0_0][_OUT_] ' $target->[1]{$mode} ' did not eval into defined data
ERROR: Target[XXX.XXX.XXX.XXX_se0_0][_IN_] ' $target->[2]{$mode} ' did not eval into defined data
ERROR: Target[XXX.XXX.XXX.XXX_se0_0][_OUT_] ' $target->[2]{$mode} ' did not eval into defined data
ERROR: Target[XXX.XXX.XXX.XXX_se0_0.240][_IN_] ' $target->[3]{$mode} ' did not eval into defined data
ERROR: Target[XXX.XXX.XXX.XXX_se0_0.240][_OUT_] ' $target->[3]{$mode} ' did not eval into defined data

After Googling for a while the error message, all the references pointed towards of "getting rid of the '*.ok' files", but since I had none of those on my system that I could tell, what I did was renaming the file for that particular device on the directory defined on the directive 'ThreshDir':

sudo mv /var/lib/mrtg/_etc_mrtg_cfgs_xxxxxx.+++++++++.cfg  /var/lib/mrtg/_etc_mrtg_cfgs_xxxxxx.+++++++++.cfg.OLD

After that, it started to work A Ok once again...

The files did actually changed, the original looked like this:

xxxx@XXX.XXX.XXX.XXX_    Descr   Ethernet0/0     1
xxxx@XXX.XXX.XXX.XXX_    Descr   Null0   3
xxxx@XXX.XXX.XXX.XXX_    Descr   Serial0/0       2
xxxx@XXX.XXX.XXX.XXX_    Descr   Serial0/0.240   4
xxxx@XXX.XXX.XXX.XXX_    Ip      XXX.XXX.XXX.XXX 1
xxxx@XXX.XXX.XXX.XXX_    Name    Et0/0   
xxxx@XXX.XXX.XXX.XXX_    Name    Nu0             3
xxxx@XXX.XXX.XXX.XXX_    Name    Se0/0   
xxxx@XXX.XXX.XXX.XXX_    Name    Se0/0.240       
xxxx@XXX.XXX.XXX.XXX_    Type    32              2
xxxx@XXX.XXX.XXX.XXX_    Type    6               1

While the new one, automagically generated right after the first MRTG run, looks like this:

xxxx@XXX.XXX.XXX.XXX_    Descr   Ethernet0/0     1
xxxx@XXX.XXX.XXX.XXX_    Descr   Null0   3
xxxx@XXX.XXX.XXX.XXX_    Descr   Serial0/0       2
xxxx@XXX.XXX.XXX.XXX_    Descr   Serial0/0.240   4
xxxx@XXX.XXX.XXX.XXX_    Eth             Dup
xxxx@XXX.XXX.XXX.XXX_    Eth     xx-xx-x-x-x-x-x-x-x-x-x-x-x-x       1
xxxx@XXX.XXX.XXX.XXX_    Ip      XXX.XXX.XXX.XXX 1
xxxx@XXX.XXX.XXX.XXX_    Ip      10.16.254.22    4
xxxx@XXX.XXX.XXX.XXX_    Name    Et0/0           1
xxxx@XXX.XXX.XXX.XXX_    Name    Nu0             3
xxxx@XXX.XXX.XXX.XXX_    Name    Se0/0           2
xxxx@XXX.XXX.XXX.XXX_    Name    Se0/0.240       4
xxxx@XXX.XXX.XXX.XXX_    Type    1               3
xxxx@XXX.XXX.XXX.XXX_    Type    32              Dup
xxxx@XXX.XXX.XXX.XXX_    Type    6               1