Translation:Someone is sending me threats on the computer.
This is the first time I come across trusler. It had better be introduced in the singular: trussel, truslen. The verb is 'true' (threaten), which I guess must be related to German 'drohen'. Oddly it is also likely to be related to English 'throes'. End of lecture. ;) (I don't know about you, but these connections with words in other languages often help me to remember a word.)