Do you have authority to write any files to that directory?
Telling us that the workstation program is 5.8 isn’t as much help as telling us what version of iSeries Access you’re using. The product is iSeries Access, not the workstation program which is only a small component of the product.
However, I think the WS 5.8 is included in iSeries Access V5R4.
I don’t know if IBM has created a PTF for PCSWS026 in V5R4, although they did for V5R2 and V5R3. You should first verify if you have the latest fix pack for V5R4 applied to your PC. If PCSWS026 doesn’t go away then, report the problem to IBM to get a PTF created.