Linux – get error “incorrect command line” when trying to extract 7zip archive on linux

I copied a large zip file to a Linux server, I didn't realise at the time that it was a 7zip file.

After some messing around I installed 7zip with "yum install p7zip" however when I try to extract the archive with

7za -x ./myarchive.zip

I get the following output

7-Zip (A) 4.61 beta Copyright (c) 1999-2008 Igor Pavlov 2008-11-23
p7zip Version 4.61 (locale=C,Utf16=off,HugeFiles=on,1 CPU)

Error:
Incorrect command line

Google is not my friend with this error, so I thought that I would try here. Debated as to if this should be SF or SU, but as it is not my computer I think it is SFs' domain.