Hi Ketie,
Not sure what version of ArcSWAT you are using.
Apparently it's a bug. In ArcSWAT 2009 doc P433, the definition of table SlopeRemap could be found: this table contains the reclass table for the multiple slope classes. This table has four columns: SlopeLo, SlopeHi, SlopeClass and SlopeName. This part of your error message "CREAT TABLE[SlopeRemap] ( {OID] AUTOINCREMENT
NOT NULL ,[SlopeLo] DOUBLE, [SlopeHi] DOUBLE ,[SlopeClass] DOUBLE, [SlopeName] TEXT(12))" is a SQL which is used to create this table in project database. However, from the error message, this SQL is used as a table name and try to this table. It certainly will crush.
It should be easy to fix this bug. Please consider to report this to ArcSWAT team. Before they fix this, a possible solution would be: Try to create this table yourself in the database manually before soil reclassification. Use the table structure corresponding to the version of ArcSWAT you are using.
Best Wishes
Zhiqiang