Can anyone spot any problems with the following command which I use to add meta data to a SQL Server table?

cdescription = [']+ALLTRIM(adstruct.definition)+[']

colname = [']+ALLTRIM(adstruct.field_name)+[']

lnRet = SQLEXEC(handle28,[execute sp_addExtendedProperty 'Description',];
+cdescription+[,'schema','dbo', 'table', 'recentclaimdet', 'column', ]+colname)

I had it working but now I must have introduced a bug that I can't see. Always returns minus 1.
Handle is a valid handle.