Error detected while processing function vimshell#switch_shell..vimshell#create_shell:
line    2:
E117: Unknown function: vimfiler#iswin
E15: Invalid expression: vimfiler#iswin() ? '[vimshell]' : '*vimshell*'
line    5:
E121: Undefined variable: l:prefix
E116: Invalid arguments for function buflisted(l:prefix.l:postfix)
E15: Invalid expression: buflisted(l:prefix.l:postfix)
line    9:
E121: Undefined variable: l:prefix
E15: Invalid expression: l:prefix.l:postfix
line   16:
E121: Undefined variable: l:bufname
E15: Invalid expression: l:bufname