How to phrase part of a conditional statement?

[bzcomputers]

The error when I try to save is this:

The following error occurred when attempting to evaluate this template:
%1$s
This is likely caused by a malformed conditional statement. It is highly recommended that you fix this error before continuing, but you may continue as-is if you wish.

If I remove the "if" the error is this:

The following error occurred when attempting to evaluate this template:
Invalid Tag Nesting
This is likely caused by a malformed conditional statement. It is highly recommended that you fix this error before continuing, but you may continue as-is if you wish.