The only solution I could recommend for removing a RIS database linkage would be to create an MDL application using mdlLinkage_deleteFromElement.
The VBA RemoveDatabaseLink method works only on a specific list of database linkages types as Jon previously indicated. GetDatabaseLinks and HasAnyDatabaseLinks provide access to the full list of database linkage ids as listed in the MDL include file:dberrs.h:
/*----------------------------------------------------------------------+
| |
| Signature words used for user data linkages. |
| |
+----------------------------------------------------------------------*/
#define INFORMIX_ID 0x3948 /* Informix user data signature - 0n14664 */
#define XBASE_ID 0x1971 /* Xbase(dBASE) user data signature */
#define DBASE_ID 0x1971 /* exists for backwards compatibility to Xbase - 0n6513 */
#define RIS_ID 0x71fb /* RIS user data signature */
#define ORACLE_ID 0x6091 /* Oracle user data signature - 0n24721 */
#define INGRES_ID 0x3a77 /* INGRES user data signature (ING) - 0n14967 */
#define SYBASE_ID 0x4F58 /* Sybase user data signature (C.G)? */
#define ODBC_ID 0x5e62 /* ODBC user data signature (ODB) - 0n24162 */
#define OLEDB_ID 0x5800 /* OLEDB user data signature */
#define BUDBC_ID 0x5834 /* BUDBC user data signature */
RemoveDatabaseLink calls the MDL function mdlLinkage_deleteFromElement. Here is a sample call from MDL:
*pVal = mdlLinkage_deleteFromElement (&elementDescrP->el, dbId, 0, NULL, linkFunc, &entLink);
Since this approach requires you to have a linkFunc to (return 1 to remove, or 0 to keep the linkage) I am not familiar with a way to accomplish this directly via VBA Declares.