Hey there,

Did you get this error while doing anything else besides playing on the client?
Also, where did you download the client from? I will ask our team about this problem, however it has never before occured to me, neither have I heard of a case like that.

Don't worry, this happens from time to time. Antivirus engines like Norton are signature based.
That means, if a legit file share the same partial pattern as a virus, the antivirus will delete it if it's recognized.

Example:
Malware file: 58 35 4f 21 50 25 40 41 50 5b 34 5c 50 5a 58 35 34 28 50 5e 29 37 43 43 29 37 7d 24 45 49 43 41 52 2d
Legit file: 38 4a c1 b8 ff 00 a1 de 58 35 34 28 50 5e 29 37 43 43 29 37 7d 24 45 49 43 41 52 2d 3c b4