If your have a String, you have to concatenate just like this:

[fieldname = ] + lc

and not like this:

[fieldname = "] + lc + ["])

>calling function)
>lc = has desired value for fieldname

lcParam = "fieldname = " + lc
n = MyCount([tablename],lcParam)

>n = MyCount([tablename],[fieldname = "] + lc + ["])

>FUNCTION MyCount
>LPARAMETERS tcTable,tcCondition
>...
>jc = [SELECT COUNT(*) AS c FROM dbo.] + tcTable + [ ] + tcTable ;
>+ IIF(EMPTY(tcCondition),[],[ WHERE ]+ tcCondition)
>lnRetVal = SQLEXEC(lnHandle,jc)